From 8cb5b0333250beb382624f626851a31f601b4830 Mon Sep 17 00:00:00 2001 From: Avi Kivity Date: Tue, 20 Mar 2007 18:40:40 +0200 Subject: [PATCH] KVM: Workaround vmx inability to virtualize the reset state The reset state has cs.selector == 0xf000 and cs.base == 0xffff0000, which aren't compatible with vm86 mode, which is used for real mode virtualization. When we create a vcpu, we set cs.base to 0xf0000, but if we get there by way of a reset, the values are inconsistent and vmx refuses to enter guest mode. Workaround by detecting the state and munging it appropriately. Signed-off-by: Avi Kivity --- drivers/kvm/vmx.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/kvm/vmx.c b/drivers/kvm/vmx.c index 0d9bf0b36d..aa7e2ba6fb 100644 --- a/drivers/kvm/vmx.c +++ b/drivers/kvm/vmx.c @@ -712,6 +712,8 @@ static void enter_rmode(struct kvm_vcpu *vcpu) vmcs_write32(GUEST_CS_AR_BYTES, 0xf3); vmcs_write32(GUEST_CS_LIMIT, 0xffff); + if (vmcs_readl(GUEST_CS_BASE) == 0xffff0000) + vmcs_writel(GUEST_CS_BASE, 0xf0000); vmcs_write16(GUEST_CS_SELECTOR, vmcs_readl(GUEST_CS_BASE) >> 4); fix_rmode_seg(VCPU_SREG_ES, &vcpu->rmode.es); -- 2.39.5