[5/6] KVM: VMX: give unrestricted guest full control of CR3
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Message ID 20180305200441.5089-6-sean.j.christopherson@intel.com
State New
Headers show

Commit Message

Sean Christopherson March 5, 2018, 8:04 p.m. UTC
Now CR3 is not forced to a host-controlled value when paging is
disabled in an unrestricted guest, CR3 load/store exiting can be
left disabled (for an unrestricted guest).  And because CR0.WP
and CR4.PAE/PSE are also not force to host-controlled values,
all of ept_update_paging_mode_cr0() is no longer needed, i.e.
skip ept_update_paging_mode_cr0() for an unrestricted guest.

Because MOV CR3 no longer exits when paging is disabled for an
unrestricted guest, vmx_decache_cr3() must always read GUEST_CR3
from the VMCS for an unrestricted guest.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/vmx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Patch
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diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bee97ba1e549..cf9e75a60035 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -4286,7 +4286,7 @@  static void vmx_decache_cr0_guest_bits(struct kvm_vcpu *vcpu)
 
 static void vmx_decache_cr3(struct kvm_vcpu *vcpu)
 {
-	if (enable_ept && is_paging(vcpu))
+	if (enable_unrestricted_guest || (enable_ept && is_paging(vcpu)))
 		vcpu->arch.cr3 = vmcs_readl(GUEST_CR3);
 	__set_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail);
 }
@@ -4423,7 +4423,7 @@  static void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 	}
 #endif
 
-	if (enable_ept)
+	if (enable_ept && !enable_unrestricted_guest)
 		ept_update_paging_mode_cr0(&hw_cr0, cr0, vcpu);
 
 	vmcs_writel(CR0_READ_SHADOW, cr0);