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.
Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
---
arch/x86/kvm/cpuid.c | 27 +++++++++++++--------------
1 file changed, 13 insertions(+), 14 deletions(-)
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index edef30359c19..f73af4a98c35 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -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;
--
2.47.0.338.g60cca15819-goog
