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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,
	Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Li RongQing <lirongqing@baidu.com>
Subject: [PATCH v2 03/23] KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target
Date: Sat,  3 Sep 2022 00:22:34 +0000	[thread overview]
Message-ID: <20220903002254.2411750-4-seanjc@google.com> (raw)
In-Reply-To: <20220903002254.2411750-1-seanjc@google.com>

Emulate ICR writes on AVIC IPI failures due to invalid targets using the
same logic as failures due to invalid types.  AVIC acceleration fails if
_any_ of the targets are invalid, and crucially VM-Exits before sending
IPIs to targets that _are_ valid.  In logical mode, the destination is a
bitmap, i.e. a single IPI can target multiple logical IDs.  Doing nothing
causes KVM to drop IPIs if at least one target is valid and at least one
target is invalid.

Fixes: 18f40c53e10f ("svm: Add VMEXIT handlers for AVIC")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
---
 arch/x86/kvm/svm/avic.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
index 4fbef2af1efc..6a3d225eb02c 100644
--- a/arch/x86/kvm/svm/avic.c
+++ b/arch/x86/kvm/svm/avic.c
@@ -502,14 +502,18 @@ int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
 	trace_kvm_avic_incomplete_ipi(vcpu->vcpu_id, icrh, icrl, id, index);
 
 	switch (id) {
+	case AVIC_IPI_FAILURE_INVALID_TARGET:
 	case AVIC_IPI_FAILURE_INVALID_INT_TYPE:
 		/*
 		 * Emulate IPIs that are not handled by AVIC hardware, which
-		 * only virtualizes Fixed, Edge-Triggered INTRs.  The exit is
-		 * a trap, e.g. ICR holds the correct value and RIP has been
-		 * advanced, KVM is responsible only for emulating the IPI.
-		 * Sadly, hardware may sometimes leave the BUSY flag set, in
-		 * which case KVM needs to emulate the ICR write as well in
+		 * only virtualizes Fixed, Edge-Triggered INTRs, and falls over
+		 * if _any_ targets are invalid, e.g. if the logical mode mask
+		 * is a superset of running vCPUs.
+		 *
+		 * The exit is a trap, e.g. ICR holds the correct value and RIP
+		 * has been advanced, KVM is responsible only for emulating the
+		 * IPI.  Sadly, hardware may sometimes leave the BUSY flag set,
+		 * in which case KVM needs to emulate the ICR write as well in
 		 * order to clear the BUSY flag.
 		 */
 		if (icrl & APIC_ICR_BUSY)
@@ -525,8 +529,6 @@ int avic_incomplete_ipi_interception(struct kvm_vcpu *vcpu)
 		 */
 		avic_kick_target_vcpus(vcpu->kvm, apic, icrl, icrh, index);
 		break;
-	case AVIC_IPI_FAILURE_INVALID_TARGET:
-		break;
 	case AVIC_IPI_FAILURE_INVALID_BACKING_PAGE:
 		WARN_ONCE(1, "Invalid backing page\n");
 		break;
-- 
2.37.2.789.g6183377224-goog


  parent reply	other threads:[~2022-09-03  0:23 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-03  0:22 [PATCH v2 00/23] KVM: x86: AVIC and local APIC fixes+cleanups Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 01/23] KVM: x86: Purge "highest ISR" cache when updating APICv state Sean Christopherson
2022-09-05 21:58   ` Paolo Bonzini
2022-09-03  0:22 ` [PATCH v2 02/23] KVM: SVM: Flush the "current" TLB when activating AVIC Sean Christopherson
2022-09-05 21:58   ` Paolo Bonzini
2022-09-03  0:22 ` Sean Christopherson [this message]
2022-09-05 21:59   ` [PATCH v2 03/23] KVM: SVM: Process ICR on AVIC IPI delivery failure due to invalid target Paolo Bonzini
2022-09-03  0:22 ` [PATCH v2 04/23] KVM: x86: Inhibit AVIC SPTEs if any vCPU enables x2APIC Sean Christopherson
2022-09-05 22:02   ` Paolo Bonzini
2022-09-13 19:52   ` Suthikulpanit, Suravee
2022-09-14  7:39     ` Sean Christopherson
2022-09-14 17:41       ` Suthikulpanit, Suravee
2022-09-16 17:47         ` Sean Christopherson
2022-09-16 19:10     ` Sean Christopherson
2022-09-20 13:07   ` Maxim Levitsky
2022-09-20 15:46     ` Sean Christopherson
2022-09-20 16:50       ` Sean Christopherson
2022-09-23 10:18         ` Maxim Levitsky
2022-09-23 10:19       ` Maxim Levitsky
2022-09-03  0:22 ` [PATCH v2 05/23] KVM: SVM: Don't put/load AVIC when setting virtual APIC mode Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 06/23] KVM: SVM: Replace "avic_mode" enum with "x2avic_enabled" boolean Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 07/23] KVM: SVM: Compute dest based on sender's x2APIC status for AVIC kick Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 08/23] KVM: SVM: Fix x2APIC Logical ID calculation for avic_kick_target_vcpus_fast Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 09/23] Revert "KVM: SVM: Use target APIC ID to complete x2AVIC IRQs when possible" Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 10/23] KVM: SVM: Document that vCPU ID == APIC ID in AVIC kick fastpatch Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 11/23] KVM: SVM: Add helper to perform final AVIC "kick" of single vCPU Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 12/23] KVM: x86: Disable APIC logical map if logical ID covers multiple MDAs Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 13/23] KVM: x86: Disable APIC logical map if vCPUs are aliased in logical mode Sean Christopherson
2022-09-13 23:32   ` Suthikulpanit, Suravee
2022-09-14  7:42     ` Sean Christopherson
2022-09-15  2:11       ` Suthikulpanit, Suravee
2022-09-16 18:52         ` Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 14/23] KVM: x86: Honor architectural behavior for aliased 8-bit APIC IDs Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 15/23] KVM: x86: Explicitly skip adding vCPU to optimized logical map if LDR==0 Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 16/23] KVM: x86: Explicitly track all possibilities for APIC map's logical modes Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 17/23] KVM: SVM: Inhibit AVIC if vCPUs are aliased in logical mode Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 18/23] KVM: SVM: Always update local APIC on writes to logical dest register Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 19/23] KVM: SVM: Update svm->ldr_reg cache even if LDR is "bad" Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 20/23] KVM: SVM: Require logical ID to be power-of-2 for AVIC entry Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 21/23] KVM: SVM: Handle multiple logical targets in AVIC kick fastpath Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 22/23] KVM: SVM: Ignore writes to Remote Read Data on AVIC write traps Sean Christopherson
2022-09-03  0:22 ` [PATCH v2 23/23] Revert "KVM: SVM: Do not throw warning when calling avic_vcpu_load on a running vcpu" Sean Christopherson

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