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authorAvi Kivity <avi@redhat.com>2010-04-08 18:19:35 +0300
committerAvi Kivity <avi@redhat.com>2010-04-20 12:59:31 +0300
commit78ac8b47c566dd6177a3b9b291b756ccb70670b7 (patch)
tree46feb3a7845c7e4a3d0c621d17b3f2593e7d756f
parent114be429c8cd44e57f312af2bbd6734e5a185b0d (diff)
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KVM: VMX: Save/restore rflags.vm correctly in real mode
Currently we set eflags.vm unconditionally when entering real mode emulation through virtual-8086 mode, and clear it unconditionally when we enter protected mode. The means that the following sequence KVM_SET_REGS (rflags.vm=1) KVM_SET_SREGS (cr0.pe=1) Ends up with rflags.vm clear due to KVM_SET_SREGS triggering enter_pmode(). Fix by shadowing rflags.vm (and rflags.iopl) correctly while in real mode: reads and writes to those bits access a shadow register instead of the actual register. Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
-rw-r--r--arch/x86/kvm/vmx.c24
1 files changed, 15 insertions, 9 deletions
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 686492ed307..bc933cfb4e6 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -77,6 +77,8 @@ module_param(emulate_invalid_guest_state, bool, S_IRUGO);
#define KVM_PMODE_VM_CR4_ALWAYS_ON (X86_CR4_PAE | X86_CR4_VMXE)
#define KVM_RMODE_VM_CR4_ALWAYS_ON (X86_CR4_VME | X86_CR4_PAE | X86_CR4_VMXE)
+#define RMODE_GUEST_OWNED_EFLAGS_BITS (~(X86_EFLAGS_IOPL | X86_EFLAGS_VM))
+
/*
* These 2 parameters are used to config the controls for Pause-Loop Exiting:
* ple_gap: upper bound on the amount of time between two successive
@@ -131,7 +133,7 @@ struct vcpu_vmx {
} host_state;
struct {
int vm86_active;
- u8 save_iopl;
+ ulong save_rflags;
struct kvm_save_segment {
u16 selector;
unsigned long base;
@@ -818,18 +820,23 @@ static void vmx_fpu_deactivate(struct kvm_vcpu *vcpu)
static unsigned long vmx_get_rflags(struct kvm_vcpu *vcpu)
{
- unsigned long rflags;
+ unsigned long rflags, save_rflags;
rflags = vmcs_readl(GUEST_RFLAGS);
- if (to_vmx(vcpu)->rmode.vm86_active)
- rflags &= ~(unsigned long)(X86_EFLAGS_IOPL | X86_EFLAGS_VM);
+ if (to_vmx(vcpu)->rmode.vm86_active) {
+ rflags &= RMODE_GUEST_OWNED_EFLAGS_BITS;
+ save_rflags = to_vmx(vcpu)->rmode.save_rflags;
+ rflags |= save_rflags & ~RMODE_GUEST_OWNED_EFLAGS_BITS;
+ }
return rflags;
}
static void vmx_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
- if (to_vmx(vcpu)->rmode.vm86_active)
+ if (to_vmx(vcpu)->rmode.vm86_active) {
+ to_vmx(vcpu)->rmode.save_rflags = rflags;
rflags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM;
+ }
vmcs_writel(GUEST_RFLAGS, rflags);
}
@@ -1483,8 +1490,8 @@ static void enter_pmode(struct kvm_vcpu *vcpu)
vmcs_write32(GUEST_TR_AR_BYTES, vmx->rmode.tr.ar);
flags = vmcs_readl(GUEST_RFLAGS);
- flags &= ~(X86_EFLAGS_IOPL | X86_EFLAGS_VM);
- flags |= (vmx->rmode.save_iopl << IOPL_SHIFT);
+ flags &= RMODE_GUEST_OWNED_EFLAGS_BITS;
+ flags |= vmx->rmode.save_rflags & ~RMODE_GUEST_OWNED_EFLAGS_BITS;
vmcs_writel(GUEST_RFLAGS, flags);
vmcs_writel(GUEST_CR4, (vmcs_readl(GUEST_CR4) & ~X86_CR4_VME) |
@@ -1557,8 +1564,7 @@ static void enter_rmode(struct kvm_vcpu *vcpu)
vmcs_write32(GUEST_TR_AR_BYTES, 0x008b);
flags = vmcs_readl(GUEST_RFLAGS);
- vmx->rmode.save_iopl
- = (flags & X86_EFLAGS_IOPL) >> IOPL_SHIFT;
+ vmx->rmode.save_rflags = flags;
flags |= X86_EFLAGS_IOPL | X86_EFLAGS_VM;