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KVM: x86: Use for-loop to iterate over XSTATE size entries

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Rework xstate_required_size() to use a for-loop and continue, to make it
more obvious that the xstate_sizes[] lookups are indeed correctly bounded,
and to make it (hopefully) easier to understand that the loop is iterating
over supported XSAVE features.

Link: https://lore.kernel.org/r/20241211013302.1347853-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson 2024-12-10 17:32:59 -08:00
parent a11128ce16
commit aa93b6f96f
1 changed files with 13 additions and 14 deletions
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27
arch/x86/kvm/cpuid.c
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@ -58,25 +58,24 @@ void __init kvm_init_xstate_sizes(void)
u32 xstate_required_size(u64 xstate_bv, bool compacted)
{
int feature_bit = 0;
u32 ret = XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET;
int i;
xstate_bv &= XFEATURE_MASK_EXTEND;
while (xstate_bv) {
if (xstate_bv & 0x1) {
struct cpuid_xstate_sizes *xs = &xstate_sizes[feature_bit];
u32 offset;
for (i = XFEATURE_YMM; i < ARRAY_SIZE(xstate_sizes) && xstate_bv; i++) {
struct cpuid_xstate_sizes *xs = &xstate_sizes[i];
u32 offset;
/* ECX[1]: 64B alignment in compacted form */
if (compacted)
offset = (xs->ecx & 0x2) ? ALIGN(ret, 64) : ret;
else
offset = xs->ebx;
ret = max(ret, offset + xs->eax);
}
if (!(xstate_bv & BIT_ULL(i)))
continue;
xstate_bv >>= 1;
feature_bit++;
/* ECX[1]: 64B alignment in compacted form */
if (compacted)
offset = (xs->ecx & 0x2) ? ALIGN(ret, 64) : ret;
else
offset = xs->ebx;
ret = max(ret, offset + xs->eax);
xstate_bv &= ~BIT_ULL(i);
}
return ret;