Commit 8cb5b033 authored Mar 20, 2007 by Avi Kivity

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 <avi@qumranet.com>

parent aac01224

drivers/kvm/vmx.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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);

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