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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2021-06-23 14:01:49 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-06-23 17:49:47 +0200 |
| commit | 71ef453355a9197fcfd8ff22391a4ad7861d79e6 (patch) | |
| tree | bde92779907c14bad580980c017fbcfb08bf7f57 /arch/x86 | |
| parent | x86/fpu: Get rid of using_compacted_format() (diff) | |
| download | linux-71ef453355a9197fcfd8ff22391a4ad7861d79e6.tar.xz linux-71ef453355a9197fcfd8ff22391a4ad7861d79e6.zip | |
x86/kvm: Avoid looking up PKRU in XSAVE buffer
PKRU is being removed from the kernel XSAVE/FPU buffers. This removal
will probably include warnings for code that look up PKRU in those
buffers.
KVM currently looks up the location of PKRU but doesn't even use the
pointer that it gets back. Rework the code to avoid calling
get_xsave_addr() except in cases where its result is actually used.
This makes the code more clear and also avoids the inevitable PKRU
warnings.
This is probably a good cleanup and could go upstream idependently
of any PKRU rework.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121453.541037562@linutronix.de
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/x86.c | 45 |
1 files changed, 24 insertions, 21 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index e0f4a46649d7..c25bf240eb26 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4604,20 +4604,21 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) */ valid = xstate_bv & ~XFEATURE_MASK_FPSSE; while (valid) { + u32 size, offset, ecx, edx; u64 xfeature_mask = valid & -valid; int xfeature_nr = fls64(xfeature_mask) - 1; - void *src = get_xsave_addr(xsave, xfeature_nr); - - if (src) { - u32 size, offset, ecx, edx; - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - if (xfeature_nr == XFEATURE_PKRU) - memcpy(dest + offset, &vcpu->arch.pkru, - sizeof(vcpu->arch.pkru)); - else - memcpy(dest + offset, src, size); + void *src; + + cpuid_count(XSTATE_CPUID, xfeature_nr, + &size, &offset, &ecx, &edx); + if (xfeature_nr == XFEATURE_PKRU) { + memcpy(dest + offset, &vcpu->arch.pkru, + sizeof(vcpu->arch.pkru)); + } else { + src = get_xsave_addr(xsave, xfeature_nr); + if (src) + memcpy(dest + offset, src, size); } valid -= xfeature_mask; @@ -4647,18 +4648,20 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src) */ valid = xstate_bv & ~XFEATURE_MASK_FPSSE; while (valid) { + u32 size, offset, ecx, edx; u64 xfeature_mask = valid & -valid; int xfeature_nr = fls64(xfeature_mask) - 1; - void *dest = get_xsave_addr(xsave, xfeature_nr); - - if (dest) { - u32 size, offset, ecx, edx; - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - if (xfeature_nr == XFEATURE_PKRU) - memcpy(&vcpu->arch.pkru, src + offset, - sizeof(vcpu->arch.pkru)); - else + + cpuid_count(XSTATE_CPUID, xfeature_nr, + &size, &offset, &ecx, &edx); + + if (xfeature_nr == XFEATURE_PKRU) { + memcpy(&vcpu->arch.pkru, src + offset, + sizeof(vcpu->arch.pkru)); + } else { + void *dest = get_xsave_addr(xsave, xfeature_nr); + + if (dest) memcpy(dest, src + offset, size); } |