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Relax the maximum allowed Secure Execution (SE) header size from
8 KiB to 1 MiB. This allows individual secure guest images to run on a
wider range of physical machines.
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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The shadow gmap returned by gmap_create_shadow() could get dropped
before taking the gmap->children_lock. This meant that the shadow gmap
was sometimes being used while its reference count was 0.
Fix this by taking the additional reference inside gmap_create_shadow()
while still holding gmap->children_lock, instead of afterwards.
Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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It is possible that walk_guest_tables() is called on a shadow gmap that
has been removed already, in which case its parent will be NULL.
In such case, return -EAGAIN and let the callers deal with it.
Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Stop using the userspace address to mark the guest page dirty.
mark_page_dirty() expects a guest frame number, but was being passed a
host virtual frame number. When slot == NULL, mark_page_dirty_in_slot()
does nothing and does not complain.
This means that in some circumstances the dirtiness of the guest page
might have been lost.
Fix by adding two fields in struct kvm_s390_adapter_int to keep the
guest addressses, and use those for mark_page_dirty().
Fixes: f65470661f36 ("KVM: s390/interrupt: do not pin adapter interrupt pages")
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add a new IOCTL to allow userspace to manipulate storage keys directly.
This will make it easier to write selftests related to storage keys.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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While userspace is allowed to have pages of any size, the new gmap
would always use 4k pages to back the guest.
Enable 1M pages for gmap.
This allows 1M pages to be used to back a guest when userspace is using
1M pages for the corresponding addresses (e.g. THP or hugetlbfs).
Remove the limitation that disallowed having nested guests and
hugepages at the same time.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Remove the PGSTE config option.
Remove all code from linux/s390 mm that involves PGSTEs.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Switch KVM/s390 to use the new gmap code.
Remove includes to <gmap.h> and include "gmap.h" instead; fix all the
existing users of the old gmap functions to use the new ones instead.
Fix guest storage key access functions to work with the new gmap.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Refactor some storage key functions to improve readability.
Introduce helper functions that will be used in the next patches.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Implement gmap_protect_asce_top_level(), which was a stub. This
function was a stub due to cross dependencies with other patches.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add some helper functions for handling multiple guest faults at the
same time.
This will be needed for VSIE, where a nested guest access also needs to
access all the page tables that map it.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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New gmap (guest map) code. This new gmap code will only be used by KVM.
This will replace the existing gmap.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to handle CMMA and the ESSA instruction.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to handle memslot creation and destruction,
additional per-pagetable data stored in the PGSTEs, mapping physical
addresses into the gmap, and marking address ranges as prefix.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions related to storage key handling.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to walk to specific table entries, or to
perform actions on a range of entries.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds functions to clear, replace or exchange DAT table
entries.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add page table management functions to be used for KVM guest (gmap)
page tables.
This patch adds the boilerplate and functions for the allocation and
deallocation of DAT tables.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add KVM-s390 specific bitfields and helper functions to manipulate DAT
tables.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Rename some functions in gaccess.c to add a _gva or _gpa suffix to
indicate whether the function accepts a virtual or a guest-absolute
address.
This makes it easier to understand the code.
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Enable KVM_GENERIC_MMU_NOTIFIER, for now with empty placeholder callbacks.
Also enable KVM_MMU_LOCKLESS_AGING and define KVM_HAVE_MMU_RWLOCK.
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Pass the gmap explicitly as parameter, instead of just using
vsie_page->gmap.
This will be used in upcoming patches.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Introduce import_lock to avoid future races when converting pages to
secure.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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Add P bit in hardware definition of region 3 and segment table entries.
Move union vaddress from kvm/gaccess.c to asm/dat_bits.h
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
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SIE may exit because of pending host work, such as handling an interrupt,
in which case VSIE rewinds the guest PSW such that it is transparently
resumed (see Fixes tag). Unlike those other places that return rc=0, this
return leaves the guest PSW in place, requiring the guest to handle a
spurious intercept. This showed up when testing heavy I/O workloads,
when multiple vcpus attempted to dispatch the same SIE block and incurred
failures inserting them into the radix tree.
Fixes: 33a729a1770b ("KVM: s390: vsie: retry SIE instruction on host intercepts")
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
[frankja@linux.ibm.com: Replaced commit message as agreed on the list]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Pull KVM updates from Paolo Bonzini:
"ARM:
- Support for userspace handling of synchronous external aborts
(SEAs), allowing the VMM to potentially handle the abort in a
non-fatal manner
- Large rework of the VGIC's list register handling with the goal of
supporting more active/pending IRQs than available list registers
in hardware. In addition, the VGIC now supports EOImode==1 style
deactivations for IRQs which may occur on a separate vCPU than the
one that acked the IRQ
- Support for FEAT_XNX (user / privileged execute permissions) and
FEAT_HAF (hardware update to the Access Flag) in the software page
table walkers and shadow MMU
- Allow page table destruction to reschedule, fixing long
need_resched latencies observed when destroying a large VM
- Minor fixes to KVM and selftests
Loongarch:
- Get VM PMU capability from HW GCFG register
- Add AVEC basic support
- Use 64-bit register definition for EIOINTC
- Add KVM timer test cases for tools/selftests
RISC/V:
- SBI message passing (MPXY) support for KVM guest
- Give a new, more specific error subcode for the case when in-kernel
AIA virtualization fails to allocate IMSIC VS-file
- Support KVM_DIRTY_LOG_INITIALLY_SET, enabling dirty log gradually
in small chunks
- Fix guest page fault within HLV* instructions
- Flush VS-stage TLB after VCPU migration for Andes cores
s390:
- Always allocate ESCA (Extended System Control Area), instead of
starting with the basic SCA and converting to ESCA with the
addition of the 65th vCPU. The price is increased number of exits
(and worse performance) on z10 and earlier processor; ESCA was
introduced by z114/z196 in 2010
- VIRT_XFER_TO_GUEST_WORK support
- Operation exception forwarding support
- Cleanups
x86:
- Skip the costly "zap all SPTEs" on an MMIO generation wrap if MMIO
SPTE caching is disabled, as there can't be any relevant SPTEs to
zap
- Relocate a misplaced export
- Fix an async #PF bug where KVM would clear the completion queue
when the guest transitioned in and out of paging mode, e.g. when
handling an SMI and then returning to paged mode via RSM
- Leave KVM's user-return notifier registered even when disabling
virtualization, as long as kvm.ko is loaded. On reboot/shutdown,
keeping the notifier registered is ok; the kernel does not use the
MSRs and the callback will run cleanly and restore host MSRs if the
CPU manages to return to userspace before the system goes down
- Use the checked version of {get,put}_user()
- Fix a long-lurking bug where KVM's lack of catch-up logic for
periodic APIC timers can result in a hard lockup in the host
- Revert the periodic kvmclock sync logic now that KVM doesn't use a
clocksource that's subject to NTP corrections
- Clean up KVM's handling of MMIO Stale Data and L1TF, and bury the
latter behind CONFIG_CPU_MITIGATIONS
- Context switch XCR0, XSS, and PKRU outside of the entry/exit fast
path; the only reason they were handled in the fast path was to
paper of a bug in the core #MC code, and that has long since been
fixed
- Add emulator support for AVX MOV instructions, to play nice with
emulated devices whose guest drivers like to access PCI BARs with
large multi-byte instructions
x86 (AMD):
- Fix a few missing "VMCB dirty" bugs
- Fix the worst of KVM's lack of EFER.LMSLE emulation
- Add AVIC support for addressing 4k vCPUs in x2AVIC mode
- Fix incorrect handling of selective CR0 writes when checking
intercepts during emulation of L2 instructions
- Fix a currently-benign bug where KVM would clobber SPEC_CTRL[63:32]
on VMRUN and #VMEXIT
- Fix a bug where KVM corrupt the guest code stream when re-injecting
a soft interrupt if the guest patched the underlying code after the
VM-Exit, e.g. when Linux patches code with a temporary INT3
- Add KVM_X86_SNP_POLICY_BITS to advertise supported SNP policy bits
to userspace, and extend KVM "support" to all policy bits that
don't require any actual support from KVM
x86 (Intel):
- Use the root role from kvm_mmu_page to construct EPTPs instead of
the current vCPU state, partly as worthwhile cleanup, but mostly to
pave the way for tracking per-root TLB flushes, and elide EPT
flushes on pCPU migration if the root is clean from a previous
flush
- Add a few missing nested consistency checks
- Rip out support for doing "early" consistency checks via hardware
as the functionality hasn't been used in years and is no longer
useful in general; replace it with an off-by-default module param
to WARN if hardware fails a check that KVM does not perform
- Fix a currently-benign bug where KVM would drop the guest's
SPEC_CTRL[63:32] on VM-Enter
- Misc cleanups
- Overhaul the TDX code to address systemic races where KVM (acting
on behalf of userspace) could inadvertantly trigger lock contention
in the TDX-Module; KVM was either working around these in weird,
ugly ways, or was simply oblivious to them (though even Yan's
devilish selftests could only break individual VMs, not the host
kernel)
- Fix a bug where KVM could corrupt a vCPU's cpu_list when freeing a
TDX vCPU, if creating said vCPU failed partway through
- Fix a few sparse warnings (bad annotation, 0 != NULL)
- Use struct_size() to simplify copying TDX capabilities to userspace
- Fix a bug where TDX would effectively corrupt user-return MSR
values if the TDX Module rejects VP.ENTER and thus doesn't clobber
host MSRs as expected
Selftests:
- Fix a math goof in mmu_stress_test when running on a single-CPU
system/VM
- Forcefully override ARCH from x86_64 to x86 to play nice with
specifying ARCH=x86_64 on the command line
- Extend a bunch of nested VMX to validate nested SVM as well
- Add support for LA57 in the core VM_MODE_xxx macro, and add a test
to verify KVM can save/restore nested VMX state when L1 is using
5-level paging, but L2 is not
- Clean up the guest paging code in anticipation of sharing the core
logic for nested EPT and nested NPT
guest_memfd:
- Add NUMA mempolicy support for guest_memfd, and clean up a variety
of rough edges in guest_memfd along the way
- Define a CLASS to automatically handle get+put when grabbing a
guest_memfd from a memslot to make it harder to leak references
- Enhance KVM selftests to make it easer to develop and debug
selftests like those added for guest_memfd NUMA support, e.g. where
test and/or KVM bugs often result in hard-to-debug SIGBUS errors
- Misc cleanups
Generic:
- Use the recently-added WQ_PERCPU when creating the per-CPU
workqueue for irqfd cleanup
- Fix a goof in the dirty ring documentation
- Fix choice of target for directed yield across different calls to
kvm_vcpu_on_spin(); the function was always starting from the first
vCPU instead of continuing the round-robin search"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (260 commits)
KVM: arm64: at: Update AF on software walk only if VM has FEAT_HAFDBS
KVM: arm64: at: Use correct HA bit in TCR_EL2 when regime is EL2
KVM: arm64: Document KVM_PGTABLE_PROT_{UX,PX}
KVM: arm64: Fix spelling mistake "Unexpeced" -> "Unexpected"
KVM: arm64: Add break to default case in kvm_pgtable_stage2_pte_prot()
KVM: arm64: Add endian casting to kvm_swap_s[12]_desc()
KVM: arm64: Fix compilation when CONFIG_ARM64_USE_LSE_ATOMICS=n
KVM: arm64: selftests: Add test for AT emulation
KVM: arm64: nv: Expose hardware access flag management to NV guests
KVM: arm64: nv: Implement HW access flag management in stage-2 SW PTW
KVM: arm64: Implement HW access flag management in stage-1 SW PTW
KVM: arm64: Propagate PTW errors up to AT emulation
KVM: arm64: Add helper for swapping guest descriptor
KVM: arm64: nv: Use pgtable definitions in stage-2 walk
KVM: arm64: Handle endianness in read helper for emulated PTW
KVM: arm64: nv: Stop passing vCPU through void ptr in S2 PTW
KVM: arm64: Call helper for reading descriptors directly
KVM: arm64: nv: Advertise support for FEAT_XNX
KVM: arm64: Teach ptdump about FEAT_XNX permissions
KVM: s390: Use generic VIRT_XFER_TO_GUEST_WORK functions
...
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https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
- SCA rework
- VIRT_XFER_TO_GUEST_WORK support
- Operation exception forwarding support
- Cleanups
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Switch to using the generic infrastructure to check for and handle pending
work before transitioning into guest mode.
xfer_to_guest_mode_handle_work() does a few more things than the current
code does when deciding whether or not to exit the __vcpu_run() loop. The
exittime tests from kvm-unit-tests, in my tests, were within a few percent
compared to before this series, which is within noise tolerance.
Co-developed-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
[frankja@linux.ibm.com: Removed semicolon]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Move enabling and disabling of interrupts around the SIE instruction to
entry code. Enabling interrupts only after the __TI_sie flag has been set
guarantees that the SIE instruction is not executed if an interrupt happens
between enabling interrupts and the execution of the SIE instruction.
Interrupt handlers and machine check handler forward the PSW to the
sie_exit label in such cases.
This is a prerequisite for VIRT_XFER_TO_GUEST_WORK to prevent that guest
context is entered when e.g. a scheduler IPI, indicating that a reschedule
is required, happens right before the SIE instruction, which could lead to
long delays.
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Tested-by: Andrew Donnellan <ajd@linux.ibm.com>
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Add a signal_exits counter for s390, as exists on arm64, loongarch, mips,
powerpc, riscv and x86.
This is used by kvm_handle_signal_exit(), which we will use when we
later enable CONFIG_VIRT_XFER_TO_GUEST_WORK.
Signed-off-by: Andrew Donnellan <ajd@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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The KMSG_COMPONENT macro is a leftover of the s390 specific "kernel
message catalog" which never made it upstream.
Remove the macro in order to get rid of a pointless indirection. Replace
all users with the string it defines. In almost all cases this leads to a
simple replacement like this:
- #define KMSG_COMPONENT "appldata"
- #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+ #define pr_fmt(fmt) "appldata: " fmt
Except for some special cases this is just mechanical/scripted work.
Acked-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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The VSIE code currently checks that the BSCA struct fits within
a page, and returns a validity exception 0x003b if it doesn't.
The BSCA is pinned in memory rather than shadowed (see block
comment at end of kvm_s390_cpu_feat_init()), so enforcing the
CPU entries to be on the same pinned page makes sense.
Except those entries aren't going to be used below the guest,
and according to the definition of that validity exception only
the header of the BSCA (everything but the CPU entries) needs to
be within a page. Adjust the alignment check to account for that.
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Setting KVM_CAP_S390_USER_OPEREXEC will forward all operation
exceptions to user space. This also includes the 0x0000 instructions
managed by KVM_CAP_S390_USER_INSTR0. It's helpful if user space wants
to emulate instructions which do not (yet) have an opcode.
While we're at it refine the documentation for
KVM_CAP_S390_USER_INSTR0.
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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kvm_s390_handle_lpsw() make use of the psw_compat_t type even though
the code has nothing to do with CONFIG_COMPAT, for which the type is
supposed to be used. Use psw32_t instead.
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
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Rename the "async" ioctl API to "unlocked" so that upcoming usage in x86's
TDX code doesn't result in a massive misnomer. To avoid having to retry
SEAMCALLs, TDX needs to acquire kvm->lock *and* all vcpu->mutex locks, and
acquiring all of those locks after/inside the current vCPU's mutex is a
non-starter. However, TDX also needs to acquire the vCPU's mutex and load
the vCPU, i.e. the handling is very much not async to the vCPU.
No functional change intended.
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Kai Huang <kai.huang@intel.com>
Link: https://patch.msgid.link/20251030200951.3402865-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Implement kvm_arch_vcpu_async_ioctl() "natively" in x86 and arm64 instead
of relying on an #ifdef'd stub, and drop HAVE_KVM_VCPU_ASYNC_IOCTL in
anticipation of using the API on x86. Once x86 uses the API, providing a
stub for one architecture and having all other architectures opt-in
requires more code than simply implementing the API in the lone holdout.
Eliminating the Kconfig will also reduce churn if the API is renamed in
the future (spoiler alert).
No functional change intended.
Acked-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Kai Huang <kai.huang@intel.com>
Link: https://patch.msgid.link/20251030200951.3402865-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
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Replace sprintf() with snprintf() when formatting debug names to prevent
potential buffer overflow. The debug_name buffer is 16 bytes, and while
unlikely to overflow with current PIDs, using snprintf() provides proper
bounds checking.
Signed-off-by: Josephine Pfeiffer <hi@josie.lol>
[frankja@linux.ibm.com: Fixed subject prefix]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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kvm_arch_vcpu_ioctl_set_fpu() always returns 0 and the local return
variable 'ret' is not used anymore. Remove it.
Signed-off-by: Thorsten Blum <thorsten.blum@linux.dev>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Since we are no longer switching from a BSCA to a ESCA we can completely
get rid of the sca_lock. The write lock was only taken for that
conversion.
After removal of the lock some local code cleanups are possible.
Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Suggested-by: Janosch Frank <frankja@linux.ibm.com>
[frankja@linux.ibm.com: Added suggested-by tag as discussed on list]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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All modern IBM Z and Linux One machines do offer support for the
Extended System Control Area (ESCA). The ESCA is available since the
z114/z196 released in 2010.
KVM needs to allocate and manage the SCA for guest VMs. Prior to this
change the SCA was setup as Basic SCA only supporting a maximum of 64
vCPUs when initializing the VM. With addition of the 65th vCPU the SCA
was needed to be converted to a ESCA.
Instead of allocating a BSCA and upgrading it for PV or when adding the
65th cpu we can always allocate the ESCA directly upon VM creation
simplifying the code in multiple places as well as completely removing
the need to convert an existing SCA.
In cases where the ESCA is not supported (z10 and earlier) the use of
the SCA entries and with that SIGP interpretation are disabled for VMs.
This increases the number of exits from the VM in multiprocessor
scenarios and thus decreases performance.
The same is true for VSIE where SIGP is currently disabled and thus no
SCA entries are used.
The only downside of the change is that we will always allocate 4 pages
for a 248 cpu ESCA instead of a single page for the BSCA per VM.
In return we can delete a bunch of checks and special handling depending
on the SCA type as well as the whole BSCA to ESCA conversion.
With that behavior change we are no longer referencing a bsca_block in
kvm->arch.sca. This will always be esca_block instead.
By specifying the type of the sca as esca_block we can simplify access
to the sca and get rid of some helpers while making the code clearer.
KVM_MAX_VCPUS is also moved to kvm_host_types to allow using this in
future type definitions.
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull more s390 updates from Alexander Gordeev:
- Compile the decompressor with -Wno-pointer-sign flag to avoid a clang
warning
- Fix incomplete conversion to flag output macros in __xsch(), to avoid
always zero return value instead of the expected condition code
- Remove superfluous newlines from inline assemblies to improve
compiler inlining decisions
- Expose firmware provided UID Checking state in sysfs regardless of
the device presence or state
- CIO does not unregister subchannels when the attached device is
invalid or unavailable. Update the purge function to remove I/O
subchannels if the device number is found on cio_ignore list
- Consolidate PAI crypto allocation and cleanup paths
- The uv_get_secret_metadata() function has been removed some few
months ago, remove also the function mention it in a comment
* tag 's390-6.18-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
s390/uv: Fix comment of uv_find_secret() function
s390/pai_crypto: Consolidate PAI crypto allocation and cleanup paths
s390/cio: Update purge function to unregister the unused subchannels
s390/pci: Expose firmware provided UID Checking state in sysfs
s390: Remove superfluous newlines from inline assemblies
s390/cio/ioasm: Fix __xsch() condition code handling
s390: Add -Wno-pointer-sign to KBUILD_CFLAGS_DECOMPRESSOR
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Use kvm_is_gpa_in_memslot() to check the validity of the notification
indicator byte address instead of open coding equivalent logic in the VFIO
AP driver.
Opportunistically use a dedicated wrapper that exists and is exported
expressly for the VFIO AP module. kvm_is_gpa_in_memslot() is generally
unsuitable for use outside of KVM; other drivers typically shouldn't rely
on KVM's memslots, and using the API requires kvm->srcu (or slots_lock) to
be held for the entire duration of the usage, e.g. to avoid TOCTOU bugs.
handle_pqap() is a bit of a special case, as it's explicitly invoked from
KVM with kvm->srcu already held, and the VFIO AP driver is in many ways an
extension of KVM that happens to live in a separate module.
Providing a dedicated API for the VFIO AP driver will allow restricting
the vast majority of generic KVM's exports to KVM submodules (e.g. to x86's
kvm-{amd,intel}.ko vendor mdoules).
No functional change intended.
Acked-by: Anthony Krowiak <akrowiak@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Link: https://lore.kernel.org/r/20250919003303.1355064-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson into HEAD
LoongArch KVM changes for v6.18
1. Add PTW feature detection on new hardware.
2. Add sign extension with kernel MMIO/IOCSR emulation.
3. Improve in-kernel IPI emulation.
4. Improve in-kernel PCH-PIC emulation.
5. Move kvm_iocsr tracepoint out of generic code.
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https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
KVM: s390: A bugfix and a performance improvement
* Improve interrupt cpu for wakeup, change the heuristic to decide wich
vCPU to deliver a floating interrupt to.
* Clear the pte when discarding a swapped page because of CMMA; this
bug was introduced in 6.16 when refactoring gmap code.
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Remove superfluous newlines from inline assemblies. Compilers use the
number of lines of inline assemblies as heuristic for the complexity
and inline decisions. Therefore inline assemblies should only contain
as many lines as required.
A lot of inline assemblies contain a superfluous newline for the last
line. Remove such newlines to improve compiler inlining decisions.
Suggested-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Alexander Gordeev <agordeev@linux.ibm.com>
Reviewed-by: Juergen Christ <jchrist@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
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Pass the right type of flag to vcpu_dat_fault_handler(); it expects a
FOLL_* flag (in particular FOLL_WRITE), but FAULT_FLAG_WRITE is passed
instead.
This still works because they happen to have the same integer value,
but it's a mistake, thus the fix.
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Fixes: 05066cafa925 ("s390/mm/fault: Handle guest-related program interrupts in KVM")
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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If mmu_notifier_register() fails, for example because a signal was
pending, the mmu_notifier will not be registered. But when the VM gets
destroyed, it will get unregistered anyway and that will cause one
extra mmdrop(), which will eventually cause the mm of the process to
be freed too early, and cause a use-after free.
This bug happens rarely, and only when secure guests are involved.
The solution is to check the return value of mmu_notifier_register()
and return it to the caller (ultimately it will be propagated all the
way to userspace). In case of -EINTR, userspace will try again.
Fixes: ca2fd0609b5d ("KVM: s390: pv: add mmu_notifier")
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Reviewed-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Steffen Eiden <seiden@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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When you run a KVM guest with vhost-net and migrate that guest to
another host, and you immediately enable postcopy after starting the
migration, there is a big chance that the network connection of the
guest won't work anymore on the destination side after the migration.
With a debug kernel v6.16.0, there is also a call trace that looks
like this:
FAULT_FLAG_ALLOW_RETRY missing 881
CPU: 6 UID: 0 PID: 549 Comm: kworker/6:2 Kdump: loaded Not tainted 6.16.0 #56 NONE
Hardware name: IBM 3931 LA1 400 (LPAR)
Workqueue: events irqfd_inject [kvm]
Call Trace:
[<00003173cbecc634>] dump_stack_lvl+0x104/0x168
[<00003173cca69588>] handle_userfault+0xde8/0x1310
[<00003173cc756f0c>] handle_pte_fault+0x4fc/0x760
[<00003173cc759212>] __handle_mm_fault+0x452/0xa00
[<00003173cc7599ba>] handle_mm_fault+0x1fa/0x6a0
[<00003173cc73409a>] __get_user_pages+0x4aa/0xba0
[<00003173cc7349e8>] get_user_pages_remote+0x258/0x770
[<000031734be6f052>] get_map_page+0xe2/0x190 [kvm]
[<000031734be6f910>] adapter_indicators_set+0x50/0x4a0 [kvm]
[<000031734be7f674>] set_adapter_int+0xc4/0x170 [kvm]
[<000031734be2f268>] kvm_set_irq+0x228/0x3f0 [kvm]
[<000031734be27000>] irqfd_inject+0xd0/0x150 [kvm]
[<00003173cc00c9ec>] process_one_work+0x87c/0x1490
[<00003173cc00dda6>] worker_thread+0x7a6/0x1010
[<00003173cc02dc36>] kthread+0x3b6/0x710
[<00003173cbed2f0c>] __ret_from_fork+0xdc/0x7f0
[<00003173cdd737ca>] ret_from_fork+0xa/0x30
3 locks held by kworker/6:2/549:
#0: 00000000800bc958 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7ee/0x1490
#1: 000030f3d527fbd0 ((work_completion)(&irqfd->inject)){+.+.}-{0:0}, at: process_one_work+0x81c/0x1490
#2: 00000000f99862b0 (&mm->mmap_lock){++++}-{3:3}, at: get_map_page+0xa8/0x190 [kvm]
The "FAULT_FLAG_ALLOW_RETRY missing" indicates that handle_userfaultfd()
saw a page fault request without ALLOW_RETRY flag set, hence userfaultfd
cannot remotely resolve it (because the caller was asking for an immediate
resolution, aka, FAULT_FLAG_NOWAIT, while remote faults can take time).
With that, get_map_page() failed and the irq was lost.
We should not be strictly in an atomic environment here and the worker
should be sleepable (the call is done during an ioctl from userspace),
so we can allow adapter_indicators_set() to just sleep waiting for the
remote fault instead.
Link: https://issues.redhat.com/browse/RHEL-42486
Signed-off-by: Peter Xu <peterx@redhat.com>
[thuth: Assembled patch description and fixed some cosmetical issues]
Signed-off-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Acked-by: Janosch Frank <frankja@linux.ibm.com>
Fixes: f65470661f36 ("KVM: s390/interrupt: do not pin adapter interrupt pages")
[frankja: Added fixes tag]
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
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Turns out that picking an idle CPU for floating interrupts has some
negative side effects. The guest will keep the IO workload on its CPU
and rather use an IPI from the interrupt CPU instead of moving workload.
For example a guest with 2 vCPUs and 1 fio process might run that fio on
vcpu1. If after diag500 both vCPUs are idle then vcpu0 is woken up. The
guest will then do an IPI from vcpu0 to vcpu1.
So lets change the heuristics and prefer the last CPU that went to
sleep. This one is likely still in halt polling and can be woken up
quickly.
This patch shows significant improvements in terms of bandwidth or
cpu consumption for fio and uperf workloads and seems to be a net
win.
Link: https://lore.kernel.org/linux-s390/20250904113927.119306-1-borntraeger@linux.ibm.com/
Reviewed-by: Christoph Schlameuß <schlameuss@de.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
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Pull kvm updates from Paolo Bonzini:
"ARM:
- Host driver for GICv5, the next generation interrupt controller for
arm64, including support for interrupt routing, MSIs, interrupt
translation and wired interrupts
- Use FEAT_GCIE_LEGACY on GICv5 systems to virtualize GICv3 VMs on
GICv5 hardware, leveraging the legacy VGIC interface
- Userspace control of the 'nASSGIcap' GICv3 feature, allowing
userspace to disable support for SGIs w/o an active state on
hardware that previously advertised it unconditionally
- Map supporting endpoints with cacheable memory attributes on
systems with FEAT_S2FWB and DIC where KVM no longer needs to
perform cache maintenance on the address range
- Nested support for FEAT_RAS and FEAT_DoubleFault2, allowing the
guest hypervisor to inject external aborts into an L2 VM and take
traps of masked external aborts to the hypervisor
- Convert more system register sanitization to the config-driven
implementation
- Fixes to the visibility of EL2 registers, namely making VGICv3
system registers accessible through the VGIC device instead of the
ONE_REG vCPU ioctls
- Various cleanups and minor fixes
LoongArch:
- Add stat information for in-kernel irqchip
- Add tracepoints for CPUCFG and CSR emulation exits
- Enhance in-kernel irqchip emulation
- Various cleanups
RISC-V:
- Enable ring-based dirty memory tracking
- Improve perf kvm stat to report interrupt events
- Delegate illegal instruction trap to VS-mode
- MMU improvements related to upcoming nested virtualization
s390x
- Fixes
x86:
- Add CONFIG_KVM_IOAPIC for x86 to allow disabling support for I/O
APIC, PIC, and PIT emulation at compile time
- Share device posted IRQ code between SVM and VMX and harden it
against bugs and runtime errors
- Use vcpu_idx, not vcpu_id, for GA log tag/metadata, to make lookups
O(1) instead of O(n)
- For MMIO stale data mitigation, track whether or not a vCPU has
access to (host) MMIO based on whether the page tables have MMIO
pfns mapped; using VFIO is prone to false negatives
- Rework the MSR interception code so that the SVM and VMX APIs are
more or less identical
- Recalculate all MSR intercepts from scratch on MSR filter changes,
instead of maintaining shadow bitmaps
- Advertise support for LKGS (Load Kernel GS base), a new instruction
that's loosely related to FRED, but is supported and enumerated
independently
- Fix a user-triggerable WARN that syzkaller found by setting the
vCPU in INIT_RECEIVED state (aka wait-for-SIPI), and then putting
the vCPU into VMX Root Mode (post-VMXON). Trying to detect every
possible path leading to architecturally forbidden states is hard
and even risks breaking userspace (if it goes from valid to valid
state but passes through invalid states), so just wait until
KVM_RUN to detect that the vCPU state isn't allowed
- Add KVM_X86_DISABLE_EXITS_APERFMPERF to allow disabling
interception of APERF/MPERF reads, so that a "properly" configured
VM can access APERF/MPERF. This has many caveats (APERF/MPERF
cannot be zeroed on vCPU creation or saved/restored on suspend and
resume, or preserved over thread migration let alone VM migration)
but can be useful whenever you're interested in letting Linux
guests see the effective physical CPU frequency in /proc/cpuinfo
- Reject KVM_SET_TSC_KHZ for vm file descriptors if vCPUs have been
created, as there's no known use case for changing the default
frequency for other VM types and it goes counter to the very reason
why the ioctl was added to the vm file descriptor. And also, there
would be no way to make it work for confidential VMs with a
"secure" TSC, so kill two birds with one stone
- Dynamically allocation the shadow MMU's hashed page list, and defer
allocating the hashed list until it's actually needed (the TDP MMU
doesn't use the list)
- Extract many of KVM's helpers for accessing architectural local
APIC state to common x86 so that they can be shared by guest-side
code for Secure AVIC
- Various cleanups and fixes
x86 (Intel):
- Preserve the host's DEBUGCTL.FREEZE_IN_SMM when running the guest.
Failure to honor FREEZE_IN_SMM can leak host state into guests
- Explicitly check vmcs12.GUEST_DEBUGCTL on nested VM-Enter to
prevent L1 from running L2 with features that KVM doesn't support,
e.g. BTF
x86 (AMD):
- WARN and reject loading kvm-amd.ko instead of panicking the kernel
if the nested SVM MSRPM offsets tracker can't handle an MSR (which
is pretty much a static condition and therefore should never
happen, but still)
- Fix a variety of flaws and bugs in the AVIC device posted IRQ code
- Inhibit AVIC if a vCPU's ID is too big (relative to what hardware
supports) instead of rejecting vCPU creation
- Extend enable_ipiv module param support to SVM, by simply leaving
IsRunning clear in the vCPU's physical ID table entry
- Disable IPI virtualization, via enable_ipiv, if the CPU is affected
by erratum #1235, to allow (safely) enabling AVIC on such CPUs
- Request GA Log interrupts if and only if the target vCPU is
blocking, i.e. only if KVM needs a notification in order to wake
the vCPU
- Intercept SPEC_CTRL on AMD if the MSR shouldn't exist according to
the vCPU's CPUID model
- Accept any SNP policy that is accepted by the firmware with respect
to SMT and single-socket restrictions. An incompatible policy
doesn't put the kernel at risk in any way, so there's no reason for
KVM to care
- Drop a superfluous WBINVD (on all CPUs!) when destroying a VM and
use WBNOINVD instead of WBINVD when possible for SEV cache
maintenance
- When reclaiming memory from an SEV guest, only do cache flushes on
CPUs that have ever run a vCPU for the guest, i.e. don't flush the
caches for CPUs that can't possibly have cache lines with dirty,
encrypted data
Generic:
- Rework irqbypass to track/match producers and consumers via an
xarray instead of a linked list. Using a linked list leads to
O(n^2) insertion times, which is hugely problematic for use cases
that create large numbers of VMs. Such use cases typically don't
actually use irqbypass, but eliminating the pointless registration
is a future problem to solve as it likely requires new uAPI
- Track irqbypass's "token" as "struct eventfd_ctx *" instead of a
"void *", to avoid making a simple concept unnecessarily difficult
to understand
- Decouple device posted IRQs from VFIO device assignment, as binding
a VM to a VFIO group is not a requirement for enabling device
posted IRQs
- Clean up and document/comment the irqfd assignment code
- Disallow binding multiple irqfds to an eventfd with a priority
waiter, i.e. ensure an eventfd is bound to at most one irqfd
through the entire host, and add a selftest to verify eventfd:irqfd
bindings are globally unique
- Add a tracepoint for KVM_SET_MEMORY_ATTRIBUTES to help debug issues
related to private <=> shared memory conversions
- Drop guest_memfd's .getattr() implementation as the VFS layer will
call generic_fillattr() if inode_operations.getattr is NULL
- Fix issues with dirty ring harvesting where KVM doesn't bound the
processing of entries in any way, which allows userspace to keep
KVM in a tight loop indefinitely
- Kill off kvm_arch_{start,end}_assignment() and x86's associated
tracking, now that KVM no longer uses assigned_device_count as a
heuristic for either irqbypass usage or MDS mitigation
Selftests:
- Fix a comment typo
- Verify KVM is loaded when getting any KVM module param so that
attempting to run a selftest without kvm.ko loaded results in a
SKIP message about KVM not being loaded/enabled (versus some random
parameter not existing)
- Skip tests that hit EACCES when attempting to access a file, and
print a "Root required?" help message. In most cases, the test just
needs to be run with elevated permissions"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (340 commits)
Documentation: KVM: Use unordered list for pre-init VGIC registers
RISC-V: KVM: Avoid re-acquiring memslot in kvm_riscv_gstage_map()
RISC-V: KVM: Use find_vma_intersection() to search for intersecting VMAs
RISC-V: perf/kvm: Add reporting of interrupt events
RISC-V: KVM: Enable ring-based dirty memory tracking
RISC-V: KVM: Fix inclusion of Smnpm in the guest ISA bitmap
RISC-V: KVM: Delegate illegal instruction fault to VS mode
RISC-V: KVM: Pass VMID as parameter to kvm_riscv_hfence_xyz() APIs
RISC-V: KVM: Factor-out g-stage page table management
RISC-V: KVM: Add vmid field to struct kvm_riscv_hfence
RISC-V: KVM: Introduce struct kvm_gstage_mapping
RISC-V: KVM: Factor-out MMU related declarations into separate headers
RISC-V: KVM: Use ncsr_xyz() in kvm_riscv_vcpu_trap_redirect()
RISC-V: KVM: Implement kvm_arch_flush_remote_tlbs_range()
RISC-V: KVM: Don't flush TLB when PTE is unchanged
RISC-V: KVM: Replace KVM_REQ_HFENCE_GVMA_VMID_ALL with KVM_REQ_TLB_FLUSH
RISC-V: KVM: Rename and move kvm_riscv_local_tlb_sanitize()
RISC-V: KVM: Drop the return value of kvm_riscv_vcpu_aia_init()
RISC-V: KVM: Check kvm_riscv_vcpu_alloc_vector_context() return value
KVM: arm64: selftests: Add FEAT_RAS EL2 registers to get-reg-list
...
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