From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: vkuznets@redhat.com, mlevitsk@redhat.com,
Sean Christopherson <sean.j.christopherson@intel.com>,
Jim Mattson <jmattson@google.com>
Subject: [PATCH 06/28] KVM: SVM: always update CR3 in VMCB
Date: Tue, 26 May 2020 13:22:46 -0400 [thread overview]
Message-ID: <20200526172308.111575-7-pbonzini@redhat.com> (raw)
In-Reply-To: <20200526172308.111575-1-pbonzini@redhat.com>
svm_load_mmu_pgd is delaying the write of GUEST_CR3 to prepare_vmcs02 as
an optimization, but this is only correct before the nested vmentry.
If userspace is modifying CR3 with KVM_SET_SREGS after the VM has
already been put in guest mode, the value of CR3 will not be updated.
Remove the optimization, which almost never triggers anyway.
This was was added in commit 689f3bf21628 ("KVM: x86: unify callbacks
to load paging root", 2020-03-16) just to keep the two vendor-specific
modules closer, but we'll fix VMX too.
Fixes: 689f3bf21628 ("KVM: x86: unify callbacks to load paging root")
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/svm/nested.c | 6 +-----
arch/x86/kvm/svm/svm.c | 16 +++++-----------
2 files changed, 6 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 166b88fc9509..81e0fbd5e267 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -256,11 +256,7 @@ void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa,
svm_set_efer(&svm->vcpu, nested_vmcb->save.efer);
svm_set_cr0(&svm->vcpu, nested_vmcb->save.cr0);
svm_set_cr4(&svm->vcpu, nested_vmcb->save.cr4);
- if (npt_enabled) {
- svm->vmcb->save.cr3 = nested_vmcb->save.cr3;
- svm->vcpu.arch.cr3 = nested_vmcb->save.cr3;
- } else
- (void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
+ (void)kvm_set_cr3(&svm->vcpu, nested_vmcb->save.cr3);
/* Guest paging mode is active - reset mmu */
kvm_mmu_reset_context(&svm->vcpu);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 270061fa6cfa..abe277a3216b 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3447,7 +3447,6 @@ static fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root)
{
struct vcpu_svm *svm = to_svm(vcpu);
- bool update_guest_cr3 = true;
unsigned long cr3;
cr3 = __sme_set(root);
@@ -3456,18 +3455,13 @@ static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, unsigned long root)
mark_dirty(svm->vmcb, VMCB_NPT);
/* Loading L2's CR3 is handled by enter_svm_guest_mode. */
- if (is_guest_mode(vcpu))
- update_guest_cr3 = false;
- else if (test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
- cr3 = vcpu->arch.cr3;
- else /* CR3 is already up-to-date. */
- update_guest_cr3 = false;
+ if (!test_bit(VCPU_EXREG_CR3, (ulong *)&vcpu->arch.regs_avail))
+ return;
+ cr3 = vcpu->arch.cr3;
}
- if (update_guest_cr3) {
- svm->vmcb->save.cr3 = cr3;
- mark_dirty(svm->vmcb, VMCB_CR);
- }
+ svm->vmcb->save.cr3 = cr3;
+ mark_dirty(svm->vmcb, VMCB_CR);
}
static int is_disabled(void)
--
2.26.2
next prev parent reply other threads:[~2020-05-26 17:25 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-26 17:22 [PATCH v2 00/28] KVM: nSVM: event fixes and migration support Paolo Bonzini
2020-05-26 17:22 ` [PATCH 01/28] KVM: x86: track manually whether an event has been injected Paolo Bonzini
2020-05-26 17:22 ` [PATCH 02/28] KVM: x86: enable event window in inject_pending_event Paolo Bonzini
2020-05-29 2:16 ` Krish Sadhukhan
2020-05-29 8:47 ` Paolo Bonzini
2020-05-26 17:22 ` [PATCH 03/28] KVM: nSVM: inject exceptions via svm_check_nested_events Paolo Bonzini
2021-03-06 1:39 ` Sean Christopherson
2021-03-06 9:26 ` Paolo Bonzini
2021-03-08 16:44 ` Sean Christopherson
2021-03-08 17:28 ` Paolo Bonzini
2021-03-08 20:43 ` Sean Christopherson
2021-03-08 22:51 ` Paolo Bonzini
2020-05-26 17:22 ` [PATCH 04/28] KVM: nSVM: remove exit_required Paolo Bonzini
2020-05-26 17:22 ` [PATCH 05/28] KVM: nSVM: correctly inject INIT vmexits Paolo Bonzini
2020-05-29 6:46 ` Krish Sadhukhan
2020-05-29 8:47 ` Paolo Bonzini
2020-05-26 17:22 ` Paolo Bonzini [this message]
2020-05-26 17:22 ` [PATCH 07/28] KVM: nVMX: always update CR3 in VMCS Paolo Bonzini
2020-05-26 17:22 ` [PATCH 08/28] KVM: nSVM: move map argument out of enter_svm_guest_mode Paolo Bonzini
2020-05-26 17:22 ` [PATCH 09/28] KVM: nSVM: extract load_nested_vmcb_control Paolo Bonzini
2020-05-26 17:22 ` [PATCH 10/28] KVM: nSVM: extract preparation of VMCB for nested run Paolo Bonzini
2020-05-26 17:22 ` [PATCH 11/28] KVM: nSVM: move MMU setup to nested_prepare_vmcb_control Paolo Bonzini
2020-05-26 17:22 ` [PATCH 12/28] KVM: nSVM: clean up tsc_offset update Paolo Bonzini
2020-05-26 17:22 ` [PATCH 13/28] KVM: nSVM: pass vmcb_control_area to copy_vmcb_control_area Paolo Bonzini
2020-05-26 17:22 ` [PATCH 14/28] KVM: nSVM: remove trailing padding for struct vmcb_control_area Paolo Bonzini
2020-05-26 17:22 ` [PATCH 15/28] KVM: nSVM: save all control fields in svm->nested Paolo Bonzini
2020-05-26 17:22 ` [PATCH 16/28] KVM: nSVM: restore clobbered INT_CTL fields after clearing VINTR Paolo Bonzini
2020-05-26 17:22 ` [PATCH 17/28] KVM: nSVM: synchronize VMCB controls updated by the processor on every vmexit Paolo Bonzini
2020-05-26 17:22 ` [PATCH 18/28] KVM: nSVM: remove unnecessary if Paolo Bonzini
2020-05-26 17:22 ` [PATCH 19/28] KVM: nSVM: extract svm_set_gif Paolo Bonzini
2020-05-26 17:23 ` [PATCH 20/28] KVM: SVM: preserve VGIF across VMCB switch Paolo Bonzini
2020-05-26 17:23 ` [PATCH 21/28] KVM: nSVM: synthesize correct EXITINTINFO on vmexit Paolo Bonzini
2020-05-26 17:23 ` [PATCH 22/28] KVM: nSVM: remove HF_VINTR_MASK Paolo Bonzini
2020-05-26 17:23 ` [PATCH 23/28] KVM: nSVM: remove HF_HIF_MASK Paolo Bonzini
2020-05-26 17:23 ` [PATCH 24/28] KVM: nSVM: split nested_vmcb_check_controls Paolo Bonzini
2020-05-26 17:23 ` [PATCH 25/28] KVM: nSVM: leave guest mode when clearing EFER.SVME Paolo Bonzini
2020-05-26 17:23 ` [PATCH 26/28] KVM: MMU: pass arbitrary CR0/CR4/EFER to kvm_init_shadow_mmu Paolo Bonzini
2020-05-26 17:23 ` [PATCH 27/28] selftests: kvm: add a SVM version of state-test Paolo Bonzini
2020-05-26 17:23 ` [PATCH 28/28] KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE Paolo Bonzini
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