- Add more CPUCFG mask bits.
- Improve feature detection.
- Add lazy load support for FPU and binary translation (LBT) register state.
- Fix return value for memory reads from and writes to in-kernel devices.
- Add support for detecting preemption from within a guest.
- Add KVM steal time test case to tools/selftests.
ARM:
- Add support for FEAT_IDST, allowing ID registers that are not
implemented to be reported as a normal trap rather than as an UNDEF
exception.
- Add sanitisation of the VTCR_EL2 register, fixing a number of
UXN/PXN/XN bugs in the process.
- Full handling of RESx bits, instead of only RES0, and resulting in
SCTLR_EL2 being added to the list of sanitised registers.
- More pKVM fixes for features that are not supposed to be exposed to
guests.
- Make sure that MTE being disabled on the pKVM host doesn't give it
the ability to attack the hypervisor.
- Allow pKVM's host stage-2 mappings to use the Force Write Back
version of the memory attributes by using the "pass-through'
encoding.
- Fix trapping of ICC_DIR_EL1 on GICv5 hosts emulating GICv3 for the
guest.
- Preliminary work for guest GICv5 support.
- A bunch of debugfs fixes, removing pointless custom iterators stored
in guest data structures.
- A small set of FPSIMD cleanups.
- Selftest fixes addressing the incorrect alignment of page
allocation.
- Other assorted low-impact fixes and spelling fixes.
RISC-V:
- Fixes for issues discoverd by KVM API fuzzing in
kvm_riscv_aia_imsic_has_attr(), kvm_riscv_aia_imsic_rw_attr(),
and kvm_riscv_vcpu_aia_imsic_update()
- Allow Zalasr, Zilsd and Zclsd extensions for Guest/VM
- Transparent huge page support for hypervisor page tables
- Adjust the number of available guest irq files based on MMIO
register sizes found in the device tree or the ACPI tables
- Add RISC-V specific paging modes to KVM selftests
- Detect paging mode at runtime for selftests
s390:
- Performance improvement for vSIE (aka nested virtualization)
- Completely new memory management. s390 was a special snowflake that enlisted
help from the architecture's page table management to build hypervisor
page tables, in particular enabling sharing the last level of page
tables. This however was a lot of code (~3K lines) in order to support
KVM, and also blocked several features. The biggest advantages is
that the page size of userspace is completely independent of the
page size used by the guest: userspace can mix normal pages, THPs and
hugetlbfs as it sees fit, and in fact transparent hugepages were not
possible before. It's also now possible to have nested guests and
guests with huge pages running on the same host.
- Maintainership change for s390 vfio-pci
- Small quality of life improvement for protected guests
x86:
- Add support for giving the guest full ownership of PMU hardware (contexted
switched around the fastpath run loop) and allowing direct access to data
MSRs and PMCs (restricted by the vPMU model). KVM still intercepts
access to control registers, e.g. to enforce event filtering and to
prevent the guest from profiling sensitive host state. This is more
accurate, since it has no risk of contention and thus dropped events, and
also has significantly less overhead.
For more information, see the commit message for merge commit bf2c3138ae
("Merge tag 'kvm-x86-pmu-6.20' of https://github.com/kvm-x86/linux into HEAD").
- Disallow changing the virtual CPU model if L2 is active, for all the same
reasons KVM disallows change the model after the first KVM_RUN.
- Fix a bug where KVM would incorrectly reject host accesses to PV MSRs
when running with KVM_CAP_ENFORCE_PV_FEATURE_CPUID enabled, even if those
were advertised as supported to userspace,
- Fix a bug with protected guest state (SEV-ES/SNP and TDX) VMs, where KVM
would attempt to read CR3 configuring an async #PF entry.
- Fail the build if EXPORT_SYMBOL_GPL or EXPORT_SYMBOL is used in KVM (for x86
only) to enforce usage of EXPORT_SYMBOL_FOR_KVM_INTERNAL. Only a few exports
that are intended for external usage, and those are allowed explicitly.
- When checking nested events after a vCPU is unblocked, ignore -EBUSY instead
of WARNing. Userspace can sometimes put the vCPU into what should be an
impossible state, and spurious exit to userspace on -EBUSY does not really
do anything to solve the issue.
- Also throw in the towel and drop the WARN on INIT/SIPI being blocked when vCPU
is in Wait-For-SIPI, which also resulted in playing whack-a-mole with syzkaller
stuffing architecturally impossible states into KVM.
- Add support for new Intel instructions that don't require anything beyond
enumerating feature flags to userspace.
- Grab SRCU when reading PDPTRs in KVM_GET_SREGS2.
- Add WARNs to guard against modifying KVM's CPU caps outside of the intended
setup flow, as nested VMX in particular is sensitive to unexpected changes
in KVM's golden configuration.
- Add a quirk to allow userspace to opt-in to actually suppress EOI broadcasts
when the suppression feature is enabled by the guest (currently limited to
split IRQCHIP, i.e. userspace I/O APIC). Sadly, simply fixing KVM to honor
Suppress EOI Broadcasts isn't an option as some userspaces have come to rely
on KVM's buggy behavior (KVM advertises Supress EOI Broadcast irrespective
of whether or not userspace I/O APIC supports Directed EOIs).
- Clean up KVM's handling of marking mapped vCPU pages dirty.
- Drop a pile of *ancient* sanity checks hidden behind in KVM's unused
ASSERT() macro, most of which could be trivially triggered by the guest
and/or user, and all of which were useless.
- Fold "struct dest_map" into its sole user, "struct rtc_status", to make it
more obvious what the weird parameter is used for, and to allow fropping
these RTC shenanigans if CONFIG_KVM_IOAPIC=n.
- Bury all of ioapic.h, i8254.h and related ioctls (including
KVM_CREATE_IRQCHIP) behind CONFIG_KVM_IOAPIC=y.
- Add a regression test for recent APICv update fixes.
- Handle "hardware APIC ISR", a.k.a. SVI, updates in kvm_apic_update_apicv()
to consolidate the updates, and to co-locate SVI updates with the updates
for KVM's own cache of ISR information.
- Drop a dead function declaration.
- Minor cleanups.
x86 (Intel):
- Rework KVM's handling of VMCS updates while L2 is active to temporarily
switch to vmcs01 instead of deferring the update until the next nested
VM-Exit. The deferred updates approach directly contributed to several
bugs, was proving to be a maintenance burden due to the difficulty in
auditing the correctness of deferred updates, and was polluting
"struct nested_vmx" with a growing pile of booleans.
- Fix an SGX bug where KVM would incorrectly try to handle EPCM page faults,
and instead always reflect them into the guest. Since KVM doesn't shadow
EPCM entries, EPCM violations cannot be due to KVM interference and
can't be resolved by KVM.
- Fix a bug where KVM would register its posted interrupt wakeup handler even
if loading kvm-intel.ko ultimately failed.
- Disallow access to vmcb12 fields that aren't fully supported, mostly to
avoid weirdness and complexity for FRED and other features, where KVM wants
enable VMCS shadowing for fields that conditionally exist.
- Print out the "bad" offsets and values if kvm-intel.ko refuses to load (or
refuses to online a CPU) due to a VMCS config mismatch.
x86 (AMD):
- Drop a user-triggerable WARN on nested_svm_load_cr3() failure.
- Add support for virtualizing ERAPS. Note, correct virtualization of ERAPS
relies on an upcoming, publicly announced change in the APM to reduce the
set of conditions where hardware (i.e. KVM) *must* flush the RAP.
- Ignore nSVM intercepts for instructions that are not supported according to
L1's virtual CPU model.
- Add support for expedited writes to the fast MMIO bus, a la VMX's fastpath
for EPT Misconfig.
- Don't set GIF when clearing EFER.SVME, as GIF exists independently of SVM,
and allow userspace to restore nested state with GIF=0.
- Treat exit_code as an unsigned 64-bit value through all of KVM.
- Add support for fetching SNP certificates from userspace.
- Fix a bug where KVM would use vmcb02 instead of vmcb01 when emulating VMLOAD
or VMSAVE on behalf of L2.
- Misc fixes and cleanups.
x86 selftests:
- Add a regression test for TPR<=>CR8 synchronization and IRQ masking.
- Overhaul selftest's MMU infrastructure to genericize stage-2 MMU support,
and extend x86's infrastructure to support EPT and NPT (for L2 guests).
- Extend several nested VMX tests to also cover nested SVM.
- Add a selftest for nested VMLOAD/VMSAVE.
- Rework the nested dirty log test, originally added as a regression test for
PML where KVM logged L2 GPAs instead of L1 GPAs, to improve test coverage
and to hopefully make the test easier to understand and maintain.
guest_memfd:
- Remove kvm_gmem_populate()'s preparation tracking and half-baked hugepage
handling. SEV/SNP was the only user of the tracking and it can do it via
the RMP.
- Retroactively document and enforce (for SNP) that KVM_SEV_SNP_LAUNCH_UPDATE
and KVM_TDX_INIT_MEM_REGION require the source page to be 4KiB aligned, to
avoid non-trivial complexity for something that no known VMM seems to be
doing and to avoid an API special case for in-place conversion, which
simply can't support unaligned sources.
- When populating guest_memfd memory, GUP the source page in common code and
pass the refcounted page to the vendor callback, instead of letting vendor
code do the heavy lifting. Doing so avoids a looming deadlock bug with
in-place due an AB-BA conflict betwee mmap_lock and guest_memfd's filemap
invalidate lock.
Generic:
- Fix a bug where KVM would ignore the vCPU's selected address space when
creating a vCPU-specific mapping of guest memory. Actually this bug
could not be hit even on x86, the only architecture with multiple
address spaces, but it's a bug nevertheless.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"Loongarch:
- Add more CPUCFG mask bits
- Improve feature detection
- Add lazy load support for FPU and binary translation (LBT) register
state
- Fix return value for memory reads from and writes to in-kernel
devices
- Add support for detecting preemption from within a guest
- Add KVM steal time test case to tools/selftests
ARM:
- Add support for FEAT_IDST, allowing ID registers that are not
implemented to be reported as a normal trap rather than as an UNDEF
exception
- Add sanitisation of the VTCR_EL2 register, fixing a number of
UXN/PXN/XN bugs in the process
- Full handling of RESx bits, instead of only RES0, and resulting in
SCTLR_EL2 being added to the list of sanitised registers
- More pKVM fixes for features that are not supposed to be exposed to
guests
- Make sure that MTE being disabled on the pKVM host doesn't give it
the ability to attack the hypervisor
- Allow pKVM's host stage-2 mappings to use the Force Write Back
version of the memory attributes by using the "pass-through'
encoding
- Fix trapping of ICC_DIR_EL1 on GICv5 hosts emulating GICv3 for the
guest
- Preliminary work for guest GICv5 support
- A bunch of debugfs fixes, removing pointless custom iterators
stored in guest data structures
- A small set of FPSIMD cleanups
- Selftest fixes addressing the incorrect alignment of page
allocation
- Other assorted low-impact fixes and spelling fixes
RISC-V:
- Fixes for issues discoverd by KVM API fuzzing in
kvm_riscv_aia_imsic_has_attr(), kvm_riscv_aia_imsic_rw_attr(), and
kvm_riscv_vcpu_aia_imsic_update()
- Allow Zalasr, Zilsd and Zclsd extensions for Guest/VM
- Transparent huge page support for hypervisor page tables
- Adjust the number of available guest irq files based on MMIO
register sizes found in the device tree or the ACPI tables
- Add RISC-V specific paging modes to KVM selftests
- Detect paging mode at runtime for selftests
s390:
- Performance improvement for vSIE (aka nested virtualization)
- Completely new memory management. s390 was a special snowflake that
enlisted help from the architecture's page table management to
build hypervisor page tables, in particular enabling sharing the
last level of page tables. This however was a lot of code (~3K
lines) in order to support KVM, and also blocked several features.
The biggest advantages is that the page size of userspace is
completely independent of the page size used by the guest:
userspace can mix normal pages, THPs and hugetlbfs as it sees fit,
and in fact transparent hugepages were not possible before. It's
also now possible to have nested guests and guests with huge pages
running on the same host
- Maintainership change for s390 vfio-pci
- Small quality of life improvement for protected guests
x86:
- Add support for giving the guest full ownership of PMU hardware
(contexted switched around the fastpath run loop) and allowing
direct access to data MSRs and PMCs (restricted by the vPMU model).
KVM still intercepts access to control registers, e.g. to enforce
event filtering and to prevent the guest from profiling sensitive
host state. This is more accurate, since it has no risk of
contention and thus dropped events, and also has significantly less
overhead.
For more information, see the commit message for merge commit
bf2c3138ae ("Merge tag 'kvm-x86-pmu-6.20' ...")
- Disallow changing the virtual CPU model if L2 is active, for all
the same reasons KVM disallows change the model after the first
KVM_RUN
- Fix a bug where KVM would incorrectly reject host accesses to PV
MSRs when running with KVM_CAP_ENFORCE_PV_FEATURE_CPUID enabled,
even if those were advertised as supported to userspace,
- Fix a bug with protected guest state (SEV-ES/SNP and TDX) VMs,
where KVM would attempt to read CR3 configuring an async #PF entry
- Fail the build if EXPORT_SYMBOL_GPL or EXPORT_SYMBOL is used in KVM
(for x86 only) to enforce usage of EXPORT_SYMBOL_FOR_KVM_INTERNAL.
Only a few exports that are intended for external usage, and those
are allowed explicitly
- When checking nested events after a vCPU is unblocked, ignore
-EBUSY instead of WARNing. Userspace can sometimes put the vCPU
into what should be an impossible state, and spurious exit to
userspace on -EBUSY does not really do anything to solve the issue
- Also throw in the towel and drop the WARN on INIT/SIPI being
blocked when vCPU is in Wait-For-SIPI, which also resulted in
playing whack-a-mole with syzkaller stuffing architecturally
impossible states into KVM
- Add support for new Intel instructions that don't require anything
beyond enumerating feature flags to userspace
- Grab SRCU when reading PDPTRs in KVM_GET_SREGS2
- Add WARNs to guard against modifying KVM's CPU caps outside of the
intended setup flow, as nested VMX in particular is sensitive to
unexpected changes in KVM's golden configuration
- Add a quirk to allow userspace to opt-in to actually suppress EOI
broadcasts when the suppression feature is enabled by the guest
(currently limited to split IRQCHIP, i.e. userspace I/O APIC).
Sadly, simply fixing KVM to honor Suppress EOI Broadcasts isn't an
option as some userspaces have come to rely on KVM's buggy behavior
(KVM advertises Supress EOI Broadcast irrespective of whether or
not userspace I/O APIC supports Directed EOIs)
- Clean up KVM's handling of marking mapped vCPU pages dirty
- Drop a pile of *ancient* sanity checks hidden behind in KVM's
unused ASSERT() macro, most of which could be trivially triggered
by the guest and/or user, and all of which were useless
- Fold "struct dest_map" into its sole user, "struct rtc_status", to
make it more obvious what the weird parameter is used for, and to
allow fropping these RTC shenanigans if CONFIG_KVM_IOAPIC=n
- Bury all of ioapic.h, i8254.h and related ioctls (including
KVM_CREATE_IRQCHIP) behind CONFIG_KVM_IOAPIC=y
- Add a regression test for recent APICv update fixes
- Handle "hardware APIC ISR", a.k.a. SVI, updates in
kvm_apic_update_apicv() to consolidate the updates, and to
co-locate SVI updates with the updates for KVM's own cache of ISR
information
- Drop a dead function declaration
- Minor cleanups
x86 (Intel):
- Rework KVM's handling of VMCS updates while L2 is active to
temporarily switch to vmcs01 instead of deferring the update until
the next nested VM-Exit.
The deferred updates approach directly contributed to several bugs,
was proving to be a maintenance burden due to the difficulty in
auditing the correctness of deferred updates, and was polluting
"struct nested_vmx" with a growing pile of booleans
- Fix an SGX bug where KVM would incorrectly try to handle EPCM page
faults, and instead always reflect them into the guest. Since KVM
doesn't shadow EPCM entries, EPCM violations cannot be due to KVM
interference and can't be resolved by KVM
- Fix a bug where KVM would register its posted interrupt wakeup
handler even if loading kvm-intel.ko ultimately failed
- Disallow access to vmcb12 fields that aren't fully supported,
mostly to avoid weirdness and complexity for FRED and other
features, where KVM wants enable VMCS shadowing for fields that
conditionally exist
- Print out the "bad" offsets and values if kvm-intel.ko refuses to
load (or refuses to online a CPU) due to a VMCS config mismatch
x86 (AMD):
- Drop a user-triggerable WARN on nested_svm_load_cr3() failure
- Add support for virtualizing ERAPS. Note, correct virtualization of
ERAPS relies on an upcoming, publicly announced change in the APM
to reduce the set of conditions where hardware (i.e. KVM) *must*
flush the RAP
- Ignore nSVM intercepts for instructions that are not supported
according to L1's virtual CPU model
- Add support for expedited writes to the fast MMIO bus, a la VMX's
fastpath for EPT Misconfig
- Don't set GIF when clearing EFER.SVME, as GIF exists independently
of SVM, and allow userspace to restore nested state with GIF=0
- Treat exit_code as an unsigned 64-bit value through all of KVM
- Add support for fetching SNP certificates from userspace
- Fix a bug where KVM would use vmcb02 instead of vmcb01 when
emulating VMLOAD or VMSAVE on behalf of L2
- Misc fixes and cleanups
x86 selftests:
- Add a regression test for TPR<=>CR8 synchronization and IRQ masking
- Overhaul selftest's MMU infrastructure to genericize stage-2 MMU
support, and extend x86's infrastructure to support EPT and NPT
(for L2 guests)
- Extend several nested VMX tests to also cover nested SVM
- Add a selftest for nested VMLOAD/VMSAVE
- Rework the nested dirty log test, originally added as a regression
test for PML where KVM logged L2 GPAs instead of L1 GPAs, to
improve test coverage and to hopefully make the test easier to
understand and maintain
guest_memfd:
- Remove kvm_gmem_populate()'s preparation tracking and half-baked
hugepage handling. SEV/SNP was the only user of the tracking and it
can do it via the RMP
- Retroactively document and enforce (for SNP) that
KVM_SEV_SNP_LAUNCH_UPDATE and KVM_TDX_INIT_MEM_REGION require the
source page to be 4KiB aligned, to avoid non-trivial complexity for
something that no known VMM seems to be doing and to avoid an API
special case for in-place conversion, which simply can't support
unaligned sources
- When populating guest_memfd memory, GUP the source page in common
code and pass the refcounted page to the vendor callback, instead
of letting vendor code do the heavy lifting. Doing so avoids a
looming deadlock bug with in-place due an AB-BA conflict betwee
mmap_lock and guest_memfd's filemap invalidate lock
Generic:
- Fix a bug where KVM would ignore the vCPU's selected address space
when creating a vCPU-specific mapping of guest memory. Actually
this bug could not be hit even on x86, the only architecture with
multiple address spaces, but it's a bug nevertheless"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (267 commits)
KVM: s390: Increase permitted SE header size to 1 MiB
MAINTAINERS: Replace backup for s390 vfio-pci
KVM: s390: vsie: Fix race in acquire_gmap_shadow()
KVM: s390: vsie: Fix race in walk_guest_tables()
KVM: s390: Use guest address to mark guest page dirty
irqchip/riscv-imsic: Adjust the number of available guest irq files
RISC-V: KVM: Transparent huge page support
RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test
RISC-V: KVM: Allow Zalasr extensions for Guest/VM
KVM: riscv: selftests: Add riscv vm satp modes
KVM: riscv: selftests: add Zilsd and Zclsd extension to get-reg-list test
riscv: KVM: allow Zilsd and Zclsd extensions for Guest/VM
RISC-V: KVM: Skip IMSIC update if vCPU IMSIC state is not initialized
RISC-V: KVM: Fix null pointer dereference in kvm_riscv_aia_imsic_rw_attr()
RISC-V: KVM: Fix null pointer dereference in kvm_riscv_aia_imsic_has_attr()
RISC-V: KVM: Remove unnecessary 'ret' assignment
KVM: s390: Add explicit padding to struct kvm_s390_keyop
KVM: LoongArch: selftests: Add steal time test case
LoongArch: KVM: Add paravirt vcpu_is_preempted() support in guest side
LoongArch: KVM: Add paravirt preempt feature in hypervisor side
...
cb5573868e