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KVM: VMX: Process CR0.PG side effects after setting CR0 assets

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Move the long mode and EPT w/o unrestricted guest side effect processing
down in vmx_set_cr0() so that the EPT && !URG case doesn't have to stuff
vcpu->arch.cr0 early.  This also fixes an oddity where CR0 might not be
marked available, i.e. the early vcpu->arch.cr0 write would appear to be
in danger of being overwritten, though that can't actually happen in the
current code since CR0.TS is the only guest-owned bit, and CR0.TS is not
read by vmx_set_cr4().

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210713163324.627647-28-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Sean Christopherson 2021-07-13 09:33:05 -07:00 committed by Paolo Bonzini
parent 908b7d43c0
commit 32437c2aea
1 changed files with 12 additions and 11 deletions
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23
arch/x86/kvm/vmx/vmx.c
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@ -3003,9 +3003,11 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu)
void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
unsigned long hw_cr0;
unsigned long hw_cr0, old_cr0_pg;
u32 tmp;
old_cr0_pg = kvm_read_cr0_bits(vcpu, X86_CR0_PG);
hw_cr0 = (cr0 & ~KVM_VM_CR0_ALWAYS_OFF);
if (is_unrestricted_guest(vcpu))
hw_cr0 |= KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST;
@ -3021,11 +3023,16 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
enter_rmode(vcpu);
}
vmcs_writel(CR0_READ_SHADOW, cr0);
vmcs_writel(GUEST_CR0, hw_cr0);
vcpu->arch.cr0 = cr0;
kvm_register_mark_available(vcpu, VCPU_EXREG_CR0);
#ifdef CONFIG_X86_64
if (vcpu->arch.efer & EFER_LME) {
if (!is_paging(vcpu) && (cr0 & X86_CR0_PG))
if (!old_cr0_pg && (cr0 & X86_CR0_PG))
enter_lmode(vcpu);
if (is_paging(vcpu) && !(cr0 & X86_CR0_PG))
else if (old_cr0_pg && !(cr0 & X86_CR0_PG))
exit_lmode(vcpu);
}
#endif
@ -3066,17 +3073,11 @@ void vmx_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
exec_controls_set(vmx, tmp);
}
if (!is_paging(vcpu) != !(cr0 & X86_CR0_PG)) {
vcpu->arch.cr0 = cr0;
/* Note, vmx_set_cr4() consumes the new vcpu->arch.cr0. */
if ((old_cr0_pg ^ cr0) & X86_CR0_PG)
vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
}
}
vmcs_writel(CR0_READ_SHADOW, cr0);
vmcs_writel(GUEST_CR0, hw_cr0);
vcpu->arch.cr0 = cr0;
kvm_register_mark_available(vcpu, VCPU_EXREG_CR0);
/* depends on vcpu->arch.cr0 to be set to a new value */
vmx->emulation_required = emulation_required(vcpu);
}