From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Jim Mattson <jmattson@google.com>,
Maxim Levitsky <mlevitsk@redhat.com>,
Oliver Upton <oupton@google.com>, Peter Shier <pshier@google.com>
Subject: [PATCH v4 13/24] KVM: x86: Formalize blocking of nested pending exceptions
Date: Sat, 23 Jul 2022 00:51:26 +0000 [thread overview]
Message-ID: <20220723005137.1649592-14-seanjc@google.com> (raw)
In-Reply-To: <20220723005137.1649592-1-seanjc@google.com>
Capture nested_run_pending as block_pending_exceptions so that the logic
of why exceptions are blocked only needs to be documented once instead of
at every place that employs the logic.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
arch/x86/kvm/svm/nested.c | 26 ++++++++++++++++----------
arch/x86/kvm/vmx/nested.c | 29 ++++++++++++++++++-----------
2 files changed, 34 insertions(+), 21 deletions(-)
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 8f991592d277..a6111392985c 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -1356,10 +1356,22 @@ static inline bool nested_exit_on_init(struct vcpu_svm *svm)
static int svm_check_nested_events(struct kvm_vcpu *vcpu)
{
- struct vcpu_svm *svm = to_svm(vcpu);
- bool block_nested_events =
- kvm_event_needs_reinjection(vcpu) || svm->nested.nested_run_pending;
struct kvm_lapic *apic = vcpu->arch.apic;
+ struct vcpu_svm *svm = to_svm(vcpu);
+ /*
+ * Only a pending nested run blocks a pending exception. If there is a
+ * previously injected event, the pending exception occurred while said
+ * event was being delivered and thus needs to be handled.
+ */
+ bool block_nested_exceptions = svm->nested.nested_run_pending;
+ /*
+ * New events (not exceptions) are only recognized at instruction
+ * boundaries. If an event needs reinjection, then KVM is handling a
+ * VM-Exit that occurred _during_ instruction execution; new events are
+ * blocked until the instruction completes.
+ */
+ bool block_nested_events = block_nested_exceptions ||
+ kvm_event_needs_reinjection(vcpu);
if (lapic_in_kernel(vcpu) &&
test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -1372,13 +1384,7 @@ static int svm_check_nested_events(struct kvm_vcpu *vcpu)
}
if (vcpu->arch.exception.pending) {
- /*
- * Only a pending nested run can block a pending exception.
- * Otherwise an injected NMI/interrupt should either be
- * lost or delivered to the nested hypervisor in the EXITINTINFO
- * vmcb field, while delivering the pending exception.
- */
- if (svm->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_exit_on_exception(svm))
return 0;
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0f5a7aec82a2..361c788a73d5 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -3899,11 +3899,23 @@ static bool nested_vmx_preemption_timer_pending(struct kvm_vcpu *vcpu)
static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
{
- struct vcpu_vmx *vmx = to_vmx(vcpu);
- unsigned long exit_qual;
- bool block_nested_events =
- vmx->nested.nested_run_pending || kvm_event_needs_reinjection(vcpu);
struct kvm_lapic *apic = vcpu->arch.apic;
+ struct vcpu_vmx *vmx = to_vmx(vcpu);
+ unsigned long exit_qual;
+ /*
+ * Only a pending nested run blocks a pending exception. If there is a
+ * previously injected event, the pending exception occurred while said
+ * event was being delivered and thus needs to be handled.
+ */
+ bool block_nested_exceptions = vmx->nested.nested_run_pending;
+ /*
+ * New events (not exceptions) are only recognized at instruction
+ * boundaries. If an event needs reinjection, then KVM is handling a
+ * VM-Exit that occurred _during_ instruction execution; new events are
+ * blocked until the instruction completes.
+ */
+ bool block_nested_events = block_nested_exceptions ||
+ kvm_event_needs_reinjection(vcpu);
if (lapic_in_kernel(vcpu) &&
test_bit(KVM_APIC_INIT, &apic->pending_events)) {
@@ -3942,15 +3954,10 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
* for TSS T flag #DBs). KVM also doesn't save/restore pending MTF
* across SMI/RSM as it should; that needs to be addressed in order to
* prioritize SMI over MTF and trap-like #DBs.
- *
- * Note that only a pending nested run can block a pending exception.
- * Otherwise an injected NMI/interrupt should either be
- * lost or delivered to the nested hypervisor in the IDT_VECTORING_INFO,
- * while delivering the pending exception.
*/
if (vcpu->arch.exception.pending &&
!(vmx_get_pending_dbg_trap(vcpu) & ~DR6_BT)) {
- if (vmx->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_vmx_check_exception(vcpu, &exit_qual))
goto no_vmexit;
@@ -3967,7 +3974,7 @@ static int vmx_check_nested_events(struct kvm_vcpu *vcpu)
}
if (vcpu->arch.exception.pending) {
- if (vmx->nested.nested_run_pending)
+ if (block_nested_exceptions)
return -EBUSY;
if (!nested_vmx_check_exception(vcpu, &exit_qual))
goto no_vmexit;
--
2.37.1.359.gd136c6c3e2-goog
next prev parent reply other threads:[~2022-07-23 0:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-23 0:51 [PATCH v4 00/24] KVM: x86: Event/exception fixes and cleanups Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 01/24] KVM: nVMX: Unconditionally purge queued/injected events on nested "exit" Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 02/24] KVM: VMX: Drop bits 31:16 when shoving exception error code into VMCS Sean Christopherson
2022-08-01 16:00 ` Maxim Levitsky
2022-07-23 0:51 ` [PATCH v4 03/24] KVM: x86: Don't check for code breakpoints when emulating on exception Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 04/24] KVM: nVMX: Treat General Detect #DB (DR7.GD=1) as fault-like Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 05/24] KVM: nVMX: Prioritize TSS T-flag #DBs over Monitor Trap Flag Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 06/24] KVM: x86: Treat #DBs from the emulator as fault-like (code and DR7.GD=1) Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 07/24] KVM: x86: Use DR7_GD macro instead of open coding check in emulator Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 08/24] KVM: nVMX: Ignore SIPI that arrives in L2 when vCPU is not in WFS Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 09/24] KVM: nVMX: Unconditionally clear mtf_pending on nested VM-Exit Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 10/24] KVM: VMX: Inject #PF on ENCLS as "emulated" #PF Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 11/24] KVM: x86: Rename kvm_x86_ops.queue_exception to inject_exception Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 12/24] KVM: x86: Make kvm_queued_exception a properly named, visible struct Sean Christopherson
2022-08-01 16:10 ` Maxim Levitsky
2022-07-23 0:51 ` Sean Christopherson [this message]
2022-07-23 0:51 ` [PATCH v4 14/24] KVM: x86: Use kvm_queue_exception_e() to queue #DF Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 15/24] KVM: x86: Hoist nested event checks above event injection logic Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 16/24] KVM: x86: Evaluate ability to inject SMI/NMI/IRQ after potential VM-Exit Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 17/24] KVM: nVMX: Add a helper to identify low-priority #DB traps Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 18/24] KVM: nVMX: Document priority of all known events on Intel CPUs Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 19/24] KVM: x86: Morph pending exceptions to pending VM-Exits at queue time Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 20/24] KVM: x86: Treat pending TRIPLE_FAULT requests as pending exceptions Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 21/24] KVM: VMX: Update MTF and ICEBP comments to document KVM's subtle behavior Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 22/24] KVM: x86: Rename inject_pending_events() to kvm_check_and_inject_events() Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 23/24] KVM: selftests: Use uapi header to get VMX and SVM exit reasons/codes Sean Christopherson
2022-07-23 0:51 ` [PATCH v4 24/24] KVM: selftests: Add an x86-only test to verify nested exception queueing Sean Christopherson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220723005137.1649592-14-seanjc@google.com \
--to=seanjc@google.com \
--cc=jmattson@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mlevitsk@redhat.com \
--cc=oupton@google.com \
--cc=pbonzini@redhat.com \
--cc=pshier@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®