From 02668b061db1b9f7f18872e594ac68e237db0bed Mon Sep 17 00:00:00 2001 From: Andre Przywara Date: Fri, 10 Jun 2011 11:35:30 +0200 Subject: [PATCH] KVM: fix XSAVE bit scanning (now properly) commit 123108f1c1aafd51d6a5c79cc04d7999dd88a930 tried to fix KVMs XSAVE valid feature scanning, but it was wrong. It was not considering the sparse nature of this bitfield, instead reading values from uninitialized members of the entries array. This patch now separates subleaf indicies from KVM's array indicies and fills the entry before querying it's value. This fixes AVX support in KVM guests. Signed-off-by: Andre Przywara Signed-off-by: Avi Kivity --- arch/x86/kvm/x86.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index ff4623b1b102..84f46074ca74 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -2447,16 +2447,17 @@ static void do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, break; } case 0xd: { - int i; + int idx, i; entry->flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; - for (i = 1; *nent < maxnent && i < 64; ++i) { - if (entry[i].eax == 0 || !supported_xcr0_bit(i)) + for (idx = 1, i = 1; *nent < maxnent && idx < 64; ++idx) { + do_cpuid_1_ent(&entry[i], function, idx); + if (entry[i].eax == 0 || !supported_xcr0_bit(idx)) continue; - do_cpuid_1_ent(&entry[i], function, i); entry[i].flags |= KVM_CPUID_FLAG_SIGNIFCANT_INDEX; ++*nent; + ++i; } break; } -- 2.20.1