linux.git/arch/x86/kernel/fpu, branch v5.17 Linux kernel source tree Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2022-02-24T22:05:49+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-02-24T22:05:49+00:00 1f840c0ef44b7304d6a58499e0e5668084c0864d Pull kvm fixes from Paolo Bonzini: "x86 host: - Expose KVM_CAP_ENABLE_CAP since it is supported - Disable KVM_HC_CLOCK_PAIRING in TSC catchup mode - Ensure async page fault token is nonzero - Fix lockdep false negative - Fix FPU migration regression from the AMX changes x86 guest: - Don't use PV TLB/IPI/yield on uniprocessor guests PPC: - reserve capability id (topic branch for ppc/kvm)" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: KVM: x86: nSVM: disallow userspace setting of MSR_AMD64_TSC_RATIO to non default value when tsc scaling disabled KVM: x86/mmu: make apf token non-zero to fix bug KVM: PPC: reserve capability 210 for KVM_CAP_PPC_AIL_MODE_3 x86/kvm: Don't use pv tlb/ipi/sched_yield if on 1 vCPU x86/kvm: Fix compilation warning in non-x86_64 builds x86/kvm/fpu: Remove kvm_vcpu_arch.guest_supported_xcr0 x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0 kvm: x86: Disable KVM_HC_CLOCK_PAIRING if tsc is in always catchup mode KVM: Fix lockdep false negative during host resume KVM: x86: Add KVM_CAP_ENABLE_CAP to x86 
Pull kvm fixes from Paolo Bonzini:
 "x86 host:

   - Expose KVM_CAP_ENABLE_CAP since it is supported

   - Disable KVM_HC_CLOCK_PAIRING in TSC catchup mode

   - Ensure async page fault token is nonzero

   - Fix lockdep false negative

   - Fix FPU migration regression from the AMX changes

  x86 guest:

   - Don't use PV TLB/IPI/yield on uniprocessor guests

  PPC:

   - reserve capability id (topic branch for ppc/kvm)"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: nSVM: disallow userspace setting of MSR_AMD64_TSC_RATIO to non default value when tsc scaling disabled
  KVM: x86/mmu: make apf token non-zero to fix bug
  KVM: PPC: reserve capability 210 for KVM_CAP_PPC_AIL_MODE_3
  x86/kvm: Don't use pv tlb/ipi/sched_yield if on 1 vCPU
  x86/kvm: Fix compilation warning in non-x86_64 builds
  x86/kvm/fpu: Remove kvm_vcpu_arch.guest_supported_xcr0
  x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0
  kvm: x86: Disable KVM_HC_CLOCK_PAIRING if tsc is in always catchup mode
  KVM: Fix lockdep false negative during host resume
  KVM: x86: Add KVM_CAP_ENABLE_CAP to x86
x86/ptrace: Fix xfpregs_set()'s incorrect xmm clearing 2022-02-18T10:23:21+00:00 Andy Lutomirski luto@kernel.org 2022-02-14T12:05:49+00:00 44cad52cc14ae10062f142ec16ede489bccf4469 xfpregs_set() handles 32-bit REGSET_XFP and 64-bit REGSET_FP. The actual code treats these regsets as modern FX state (i.e. the beginning part of XSTATE). The declarations of the regsets thought they were the legacy i387 format. The code thought they were the 32-bit (no xmm8..15) variant of XSTATE and, for good measure, made the high bits disappear by zeroing the wrong part of the buffer. The latter broke ptrace, and everything else confused anyone trying to understand the code. In particular, the nonsense definitions of the regsets confused me when I wrote this code. Clean this all up. Change the declarations to match reality (which shouldn't change the generated code, let alone the ABI) and fix xfpregs_set() to clear the correct bits and to only do so for 32-bit callers. Fixes: 6164331d15f7 ("x86/fpu: Rewrite xfpregs_set()") Reported-by: Luís Ferreira <contact@lsferreira.net> Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Cc: <stable@vger.kernel.org> Link: https://bugzilla.kernel.org/show_bug.cgi?id=215524 Link: https://lore.kernel.org/r/YgpFnZpF01WwR8wU@zn.tnic 
xfpregs_set() handles 32-bit REGSET_XFP and 64-bit REGSET_FP. The actual
code treats these regsets as modern FX state (i.e. the beginning part of
XSTATE). The declarations of the regsets thought they were the legacy
i387 format. The code thought they were the 32-bit (no xmm8..15) variant
of XSTATE and, for good measure, made the high bits disappear by zeroing
the wrong part of the buffer. The latter broke ptrace, and everything
else confused anyone trying to understand the code. In particular, the
nonsense definitions of the regsets confused me when I wrote this code.

Clean this all up. Change the declarations to match reality (which
shouldn't change the generated code, let alone the ABI) and fix
xfpregs_set() to clear the correct bits and to only do so for 32-bit
callers.

Fixes: 6164331d15f7 ("x86/fpu: Rewrite xfpregs_set()")
Reported-by: Luís Ferreira <contact@lsferreira.net>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215524
Link: https://lore.kernel.org/r/YgpFnZpF01WwR8wU@zn.tnic
x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0 2022-02-17T15:05:57+00:00 Leonardo Bras leobras@redhat.com 2022-02-17T05:30:29+00:00 ad856280ddea3401e1f5060ef20e6de9f6122c76 During host/guest switch (like in kvm_arch_vcpu_ioctl_run()), the kernel swaps the fpu between host/guest contexts, by using fpu_swap_kvm_fpstate(). When xsave feature is available, the fpu swap is done by: - xsave(s) instruction, with guest's fpstate->xfeatures as mask, is used to store the current state of the fpu registers to a buffer. - xrstor(s) instruction, with (fpu_kernel_cfg.max_features & XFEATURE_MASK_FPSTATE) as mask, is used to put the buffer into fpu regs. For xsave(s) the mask is used to limit what parts of the fpu regs will be copied to the buffer. Likewise on xrstor(s), the mask is used to limit what parts of the fpu regs will be changed. The mask for xsave(s), the guest's fpstate->xfeatures, is defined on kvm_arch_vcpu_create(), which (in summary) sets it to all features supported by the cpu which are enabled on kernel config. This means that xsave(s) will save to guest buffer all the fpu regs contents the cpu has enabled when the guest is paused, even if they are not used. This would not be an issue, if xrstor(s) would also do that. xrstor(s)'s mask for host/guest swap is basically every valid feature contained in kernel config, except XFEATURE_MASK_PKRU. Accordingto kernel src, it is instead switched in switch_to() and flush_thread(). Then, the following happens with a host supporting PKRU starts a guest that does not support it: 1 - Host has XFEATURE_MASK_PKRU set. 1st switch to guest, 2 - xsave(s) fpu regs to host fpustate (buffer has XFEATURE_MASK_PKRU) 3 - xrstor(s) guest fpustate to fpu regs (fpu regs have XFEATURE_MASK_PKRU) 4 - guest runs, then switch back to host, 5 - xsave(s) fpu regs to guest fpstate (buffer now have XFEATURE_MASK_PKRU) 6 - xrstor(s) host fpstate to fpu regs. 7 - kvm_vcpu_ioctl_x86_get_xsave() copy guest fpstate to userspace (with XFEATURE_MASK_PKRU, which should not be supported by guest vcpu) On 5, even though the guest does not support PKRU, it does have the flag set on guest fpstate, which is transferred to userspace via vcpu ioctl KVM_GET_XSAVE. This becomes a problem when the user decides on migrating the above guest to another machine that does not support PKRU: the new host restores guest's fpu regs to as they were before (xrstor(s)), but since the new host don't support PKRU, a general-protection exception ocurs in xrstor(s) and that crashes the guest. This can be solved by making the guest's fpstate->user_xfeatures hold a copy of guest_supported_xcr0. This way, on 7 the only flags copied to userspace will be the ones compatible to guest requirements, and thus there will be no issue during migration. As a bonus, it will also fail if userspace tries to set fpu features (with the KVM_SET_XSAVE ioctl) that are not compatible to the guest configuration. Such features will never be returned by KVM_GET_XSAVE or KVM_GET_XSAVE2. Also, since kvm_vcpu_after_set_cpuid() now sets fpstate->user_xfeatures, there is not need to set it in kvm_check_cpuid(). So, change fpstate_realloc() so it does not touch fpstate->user_xfeatures if a non-NULL guest_fpu is passed, which is the case when kvm_check_cpuid() calls it. Signed-off-by: Leonardo Bras <leobras@redhat.com> Message-Id: <20220217053028.96432-2-leobras@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
During host/guest switch (like in kvm_arch_vcpu_ioctl_run()), the kernel
swaps the fpu between host/guest contexts, by using fpu_swap_kvm_fpstate().

When xsave feature is available, the fpu swap is done by:
- xsave(s) instruction, with guest's fpstate->xfeatures as mask, is used
  to store the current state of the fpu registers to a buffer.
- xrstor(s) instruction, with (fpu_kernel_cfg.max_features &
  XFEATURE_MASK_FPSTATE) as mask, is used to put the buffer into fpu regs.

For xsave(s) the mask is used to limit what parts of the fpu regs will
be copied to the buffer. Likewise on xrstor(s), the mask is used to
limit what parts of the fpu regs will be changed.

The mask for xsave(s), the guest's fpstate->xfeatures, is defined on
kvm_arch_vcpu_create(), which (in summary) sets it to all features
supported by the cpu which are enabled on kernel config.

This means that xsave(s) will save to guest buffer all the fpu regs
contents the cpu has enabled when the guest is paused, even if they
are not used.

This would not be an issue, if xrstor(s) would also do that.

xrstor(s)'s mask for host/guest swap is basically every valid feature
contained in kernel config, except XFEATURE_MASK_PKRU.
Accordingto kernel src, it is instead switched in switch_to() and
flush_thread().

Then, the following happens with a host supporting PKRU starts a
guest that does not support it:
1 - Host has XFEATURE_MASK_PKRU set. 1st switch to guest,
2 - xsave(s) fpu regs to host fpustate (buffer has XFEATURE_MASK_PKRU)
3 - xrstor(s) guest fpustate to fpu regs (fpu regs have XFEATURE_MASK_PKRU)
4 - guest runs, then switch back to host,
5 - xsave(s) fpu regs to guest fpstate (buffer now have XFEATURE_MASK_PKRU)
6 - xrstor(s) host fpstate to fpu regs.
7 - kvm_vcpu_ioctl_x86_get_xsave() copy guest fpstate to userspace (with
    XFEATURE_MASK_PKRU, which should not be supported by guest vcpu)

On 5, even though the guest does not support PKRU, it does have the flag
set on guest fpstate, which is transferred to userspace via vcpu ioctl
KVM_GET_XSAVE.

This becomes a problem when the user decides on migrating the above guest
to another machine that does not support PKRU: the new host restores
guest's fpu regs to as they were before (xrstor(s)), but since the new
host don't support PKRU, a general-protection exception ocurs in xrstor(s)
and that crashes the guest.

This can be solved by making the guest's fpstate->user_xfeatures hold
a copy of guest_supported_xcr0. This way, on 7 the only flags copied to
userspace will be the ones compatible to guest requirements, and thus
there will be no issue during migration.

As a bonus, it will also fail if userspace tries to set fpu features
(with the KVM_SET_XSAVE ioctl) that are not compatible to the guest
configuration.  Such features will never be returned by KVM_GET_XSAVE
or KVM_GET_XSAVE2.

Also, since kvm_vcpu_after_set_cpuid() now sets fpstate->user_xfeatures,
there is not need to set it in kvm_check_cpuid(). So, change
fpstate_realloc() so it does not touch fpstate->user_xfeatures if a
non-NULL guest_fpu is passed, which is the case when kvm_check_cpuid()
calls it.

Signed-off-by: Leonardo Bras <leobras@redhat.com>
Message-Id: <20220217053028.96432-2-leobras@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm 2022-01-16T14:15:14+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-01-16T14:15:14+00:00 79e06c4c4950be2abd8ca5d2428a8c915aa62c24 Pull kvm updates from Paolo Bonzini: "RISCV: - Use common KVM implementation of MMU memory caches - SBI v0.2 support for Guest - Initial KVM selftests support - Fix to avoid spurious virtual interrupts after clearing hideleg CSR - Update email address for Anup and Atish ARM: - Simplification of the 'vcpu first run' by integrating it into KVM's 'pid change' flow - Refactoring of the FP and SVE state tracking, also leading to a simpler state and less shared data between EL1 and EL2 in the nVHE case - Tidy up the header file usage for the nvhe hyp object - New HYP unsharing mechanism, finally allowing pages to be unmapped from the Stage-1 EL2 page-tables - Various pKVM cleanups around refcounting and sharing - A couple of vgic fixes for bugs that would trigger once the vcpu xarray rework is merged, but not sooner - Add minimal support for ARMv8.7's PMU extension - Rework kvm_pgtable initialisation ahead of the NV work - New selftest for IRQ injection - Teach selftests about the lack of default IPA space and page sizes - Expand sysreg selftest to deal with Pointer Authentication - The usual bunch of cleanups and doc update s390: - fix sigp sense/start/stop/inconsistency - cleanups x86: - Clean up some function prototypes more - improved gfn_to_pfn_cache with proper invalidation, used by Xen emulation - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery - completely remove potential TOC/TOU races in nested SVM consistency checks - update some PMCs on emulated instructions - Intel AMX support (joint work between Thomas and Intel) - large MMU cleanups - module parameter to disable PMU virtualization - cleanup register cache - first part of halt handling cleanups - Hyper-V enlightened MSR bitmap support for nested hypervisors Generic: - clean up Makefiles - introduce CONFIG_HAVE_KVM_DIRTY_RING - optimize memslot lookup using a tree - optimize vCPU array usage by converting to xarray" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (268 commits) x86/fpu: Fix inline prefix warnings selftest: kvm: Add amx selftest selftest: kvm: Move struct kvm_x86_state to header selftest: kvm: Reorder vcpu_load_state steps for AMX kvm: x86: Disable interception for IA32_XFD on demand x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() kvm: selftests: Add support for KVM_CAP_XSAVE2 kvm: x86: Add support for getting/setting expanded xstate buffer x86/fpu: Add uabi_size to guest_fpu kvm: x86: Add CPUID support for Intel AMX kvm: x86: Add XCR0 support for Intel AMX kvm: x86: Disable RDMSR interception of IA32_XFD_ERR kvm: x86: Emulate IA32_XFD_ERR for guest kvm: x86: Intercept #NM for saving IA32_XFD_ERR x86/fpu: Prepare xfd_err in struct fpu_guest kvm: x86: Add emulation for IA32_XFD x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation kvm: x86: Enable dynamic xfeatures at KVM_SET_CPUID2 x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM x86/fpu: Add guest support to xfd_enable_feature() ... 
Pull kvm updates from Paolo Bonzini:
 "RISCV:

   - Use common KVM implementation of MMU memory caches

   - SBI v0.2 support for Guest

   - Initial KVM selftests support

   - Fix to avoid spurious virtual interrupts after clearing hideleg CSR

   - Update email address for Anup and Atish

  ARM:

   - Simplification of the 'vcpu first run' by integrating it into KVM's
     'pid change' flow

   - Refactoring of the FP and SVE state tracking, also leading to a
     simpler state and less shared data between EL1 and EL2 in the nVHE
     case

   - Tidy up the header file usage for the nvhe hyp object

   - New HYP unsharing mechanism, finally allowing pages to be unmapped
     from the Stage-1 EL2 page-tables

   - Various pKVM cleanups around refcounting and sharing

   - A couple of vgic fixes for bugs that would trigger once the vcpu
     xarray rework is merged, but not sooner

   - Add minimal support for ARMv8.7's PMU extension

   - Rework kvm_pgtable initialisation ahead of the NV work

   - New selftest for IRQ injection

   - Teach selftests about the lack of default IPA space and page sizes

   - Expand sysreg selftest to deal with Pointer Authentication

   - The usual bunch of cleanups and doc update

  s390:

   - fix sigp sense/start/stop/inconsistency

   - cleanups

  x86:

   - Clean up some function prototypes more

   - improved gfn_to_pfn_cache with proper invalidation, used by Xen
     emulation

   - add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery

   - completely remove potential TOC/TOU races in nested SVM consistency
     checks

   - update some PMCs on emulated instructions

   - Intel AMX support (joint work between Thomas and Intel)

   - large MMU cleanups

   - module parameter to disable PMU virtualization

   - cleanup register cache

   - first part of halt handling cleanups

   - Hyper-V enlightened MSR bitmap support for nested hypervisors

  Generic:

   - clean up Makefiles

   - introduce CONFIG_HAVE_KVM_DIRTY_RING

   - optimize memslot lookup using a tree

   - optimize vCPU array usage by converting to xarray"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (268 commits)
  x86/fpu: Fix inline prefix warnings
  selftest: kvm: Add amx selftest
  selftest: kvm: Move struct kvm_x86_state to header
  selftest: kvm: Reorder vcpu_load_state steps for AMX
  kvm: x86: Disable interception for IA32_XFD on demand
  x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state()
  kvm: selftests: Add support for KVM_CAP_XSAVE2
  kvm: x86: Add support for getting/setting expanded xstate buffer
  x86/fpu: Add uabi_size to guest_fpu
  kvm: x86: Add CPUID support for Intel AMX
  kvm: x86: Add XCR0 support for Intel AMX
  kvm: x86: Disable RDMSR interception of IA32_XFD_ERR
  kvm: x86: Emulate IA32_XFD_ERR for guest
  kvm: x86: Intercept #NM for saving IA32_XFD_ERR
  x86/fpu: Prepare xfd_err in struct fpu_guest
  kvm: x86: Add emulation for IA32_XFD
  x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation
  kvm: x86: Enable dynamic xfeatures at KVM_SET_CPUID2
  x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM
  x86/fpu: Add guest support to xfd_enable_feature()
  ...
x86/fpu: Fix inline prefix warnings 2022-01-14T18:48:38+00:00 Yang Zhong yang.zhong@intel.com 2022-01-13T18:08:25+00:00 c862dcd199759d4a45e65dab47b03e3e8a144e3a Fix sparse warnings in xstate and remove inline prefix. Fixes: 980fe2fddcff ("x86/fpu: Extend fpu_xstate_prctl() with guest permissions") Signed-off-by: Yang Zhong <yang.zhong@intel.com> Reported-by: kernel test robot <lkp@intel.com> Message-Id: <20220113180825.322333-1-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Fix sparse warnings in xstate and remove inline prefix.

Fixes: 980fe2fddcff ("x86/fpu: Extend fpu_xstate_prctl() with guest permissions")
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Reported-by: kernel test robot <lkp@intel.com>
Message-Id: <20220113180825.322333-1-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/fpu: Provide fpu_sync_guest_vmexit_xfd_state() 2022-01-14T18:44:42+00:00 Thomas Gleixner tglx@linutronix.de 2022-01-05T12:35:31+00:00 5429cead01192ff4019ea0b13316268d14fd1ec2 KVM can disable the write emulation for the XFD MSR when the vCPU's fpstate is already correctly sized to reduce the overhead. When write emulation is disabled the XFD MSR state after a VMEXIT is unknown and therefore not in sync with the software states in fpstate and the per CPU XFD cache. Provide fpu_sync_guest_vmexit_xfd_state() which has to be invoked after a VMEXIT before enabling interrupts when write emulation is disabled for the XFD MSR. It could be invoked unconditionally even when write emulation is enabled for the price of a pointless MSR read. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-21-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
KVM can disable the write emulation for the XFD MSR when the vCPU's fpstate
is already correctly sized to reduce the overhead.

When write emulation is disabled the XFD MSR state after a VMEXIT is
unknown and therefore not in sync with the software states in fpstate and
the per CPU XFD cache.

Provide fpu_sync_guest_vmexit_xfd_state() which has to be invoked after a
VMEXIT before enabling interrupts when write emulation is disabled for the
XFD MSR.

It could be invoked unconditionally even when write emulation is enabled
for the price of a pointless MSR read.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-21-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/fpu: Add uabi_size to guest_fpu 2022-01-14T18:44:40+00:00 Thomas Gleixner tglx@linutronix.de 2022-01-05T12:35:28+00:00 c60427dd50ba9b20063ccaed0e98d62e886d7a3b Userspace needs to inquire KVM about the buffer size to work with the new KVM_SET_XSAVE and KVM_GET_XSAVE2. Add the size info to guest_fpu for KVM to access. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Wei Wang <wei.w.wang@intel.com> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-18-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Userspace needs to inquire KVM about the buffer size to work
with the new KVM_SET_XSAVE and KVM_GET_XSAVE2. Add the size info
to guest_fpu for KVM to access.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-18-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/fpu: Provide fpu_update_guest_xfd() for IA32_XFD emulation 2022-01-14T18:43:22+00:00 Kevin Tian kevin.tian@intel.com 2022-01-05T12:35:20+00:00 8eb9a48ac1e86a8a59f7123b529d6e498fb1f163 Guest XFD can be updated either in the emulation path or in the restore path. Provide a wrapper to update guest_fpu::fpstate::xfd. If the guest fpstate is currently in-use, also update the per-cpu xfd cache and the actual MSR. Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-10-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Guest XFD can be updated either in the emulation path or in the
restore path.

Provide a wrapper to update guest_fpu::fpstate::xfd. If the guest
fpstate is currently in-use, also update the per-cpu xfd cache and
the actual MSR.

Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-10-yang.zhong@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/fpu: Provide fpu_enable_guest_xfd_features() for KVM 2022-01-14T18:43:21+00:00 Sean Christopherson seanjc@google.com 2022-01-05T12:35:18+00:00 0781d60f658e25fbad3b6e4261f54eb1cd3dc302 Provide a wrapper for expanding the guest fpstate buffer according to requested xfeatures. KVM wants to call this wrapper to manage any dynamic xstate used by the guest. Suggested-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Sean Christopherson <seanjc@google.com> Signed-off-by: Kevin Tian <kevin.tian@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-Id: <20220105123532.12586-8-yang.zhong@intel.com> [Remove unnecessary 32-bit check. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Provide a wrapper for expanding the guest fpstate buffer according
to requested xfeatures. KVM wants to call this wrapper to manage
any dynamic xstate used by the guest.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20220105123532.12586-8-yang.zhong@intel.com>
[Remove unnecessary 32-bit check. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/fpu: Add guest support to xfd_enable_feature() 2022-01-14T18:43:11+00:00 Thomas Gleixner tglx@linutronix.de 2022-01-05T12:35:17+00:00 c270ce393dfd700e7510a4579568deeefba954fd Guest support for dynamically enabled FPU features requires a few modifications to the enablement function which is currently invoked from the #NM handler: 1) Use guest permissions and sizes for the update 2) Update fpu_guest state accordingly 3) Take into account that the enabling can be triggered either from a running guest via XSETBV and MSR_IA32_XFD write emulation or from a guest restore. In the latter case the guests fpstate is not the current tasks active fpstate. Split the function and implement the guest mechanics throughout the callchain. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Jing Liu <jing2.liu@intel.com> Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <20220105123532.12586-7-yang.zhong@intel.com> [Add 32-bit stub for __xfd_enable_feature. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Guest support for dynamically enabled FPU features requires a few
modifications to the enablement function which is currently invoked from
the #NM handler:

  1) Use guest permissions and sizes for the update

  2) Update fpu_guest state accordingly

  3) Take into account that the enabling can be triggered either from a
     running guest via XSETBV and MSR_IA32_XFD write emulation or from
     a guest restore. In the latter case the guests fpstate is not the
     current tasks active fpstate.

Split the function and implement the guest mechanics throughout the
callchain.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
Message-Id: <20220105123532.12586-7-yang.zhong@intel.com>
[Add 32-bit stub for __xfd_enable_feature. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>