Commit f2463247 authored Apr 28, 2016 by Bruce Rogers Committed by Radim Krčmář Apr 29, 2016

KVM: x86: fix ordering of cr0 initialization code in vmx_cpu_reset



Commit d28bc9dd reversed the order of two lines which initialize cr0,
allowing the current (old) cr0 value to mess up vcpu initialization.
This was observed in the checks for cr0 X86_CR0_WP bit in the context of
kvm_mmu_reset_context(). Besides, setting vcpu->arch.cr0 after vmx_set_cr0()
is completely redundant. Change the order back to ensure proper vcpu
initialization.

The combination of booting with ovmf firmware when guest vcpus > 1 and kvm's
ept=N option being set results in a VM-entry failure. This patch fixes that.

Fixes: d28bc9dd ("KVM: x86: INIT and reset sequences are different")
Cc: stable@vger.kernel.org
Signed-off-by: Bruce Rogers <brogers@suse.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

parent 1f644a73

arch/x86/kvm/vmx.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -5046,8 +5046,8 @@ static void vmx_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
		vmcs_write16(VIRTUAL_PROCESSOR_ID, vmx->vpid);

		cr0 = X86_CR0_NW \| X86_CR0_CD \| X86_CR0_ET;
		vmx_set_cr0(vcpu, cr0); /* enter rmode */
		vmx->vcpu.arch.cr0 = cr0;
		vmx_set_cr0(vcpu, cr0); /* enter rmode */
		vmx_set_cr4(vcpu, 0);
		vmx_set_efer(vcpu, 0);
		vmx_fpu_activate(vcpu);

Admin message