From 6fb6d245546d3ae48c4cb764b3593e4739aa1364 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Sun, 6 Dec 2009 15:51:24 +0100 Subject: [PATCH] kvm: x86: Fix initial kvm_has_msr_star KVM_GET_MSR_INDEX_LIST returns -E2BIG when the provided space is too small for all MSRs. But this is precisely the error we trigger with the initial request in order to obtain that size. Do not fail in that case. This caused a subtle corruption of the guest state as MSR_STAR was not properly saved/restored. The corruption became visible with latest kvm optimizing the MSR updates. Signed-off-by: Jan Kiszka Signed-off-by: Anthony Liguori --- target-i386/kvm.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 3b61a7fc5d..88b504c34e 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -244,9 +244,9 @@ static int kvm_has_msr_star(CPUState *env) * save/restore */ msr_list.nmsrs = 0; ret = kvm_ioctl(env->kvm_state, KVM_GET_MSR_INDEX_LIST, &msr_list); - if (ret < 0) + if (ret < 0 && ret != -E2BIG) { return 0; - + } /* Old kernel modules had a bug and could write beyond the provided memory. Allocate at least a safe amount of 1K. */ kvm_msr_list = qemu_mallocz(MAX(1024, sizeof(msr_list) +