From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4D198392837; Mon, 18 May 2026 20:25:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779135927; cv=none; b=bSPizq8G4oOBb5r2h73+5MlFg1tWjjGfRBys0MYMhUOSlyjdlOwxrbXvc9i3/NDGpgeJIIn7pb8b7NC2309SfS8Fg1ODeOzBJa3Z+992G6RZ4VcyHVoZZz6sC9wrvs+Np0+VGD7qFITOggSaarqhyy7Se3Wm4pbzgvPpHMlNQXw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779135927; c=relaxed/simple; bh=dTzJGsHSZ8xqNjuDFrBzWN7hB/SUmhWgE/soZ0ivTrc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ebdXCREpHT1yZVc0Zx0zghFooWNtag90JLg+L+l/z3ke0LLFcClBFV9iJa0RtRXjWBkeDaNrFwkN/7in1O7ZSXOd0L3vQHFbi2/NS2VnbRPG+rcXE0AIdlkJ/KnzE8rgwgzNvwhM4NY1gJqgiiVyiGt2KWB3nIE8C0UB4wag5VY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=WgS0Xnag; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="WgS0Xnag" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7284C2BCC6; Mon, 18 May 2026 20:25:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779135927; bh=dTzJGsHSZ8xqNjuDFrBzWN7hB/SUmhWgE/soZ0ivTrc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=WgS0Xnagi5hvlqRSd1uaKL28Dup8ukB6XofSFo1/iq3XVPFahNA3301Bl8KrPVVTB uwxWZMinPC3B1l42OooiSOckKNEidbHew9Esa5uyCo2KxaHH0R4gJW/ft4KifnnslI JBGhKOrsFfe5DheeSdMBN5B2b2jBt2vTv0jddYaYW5HSBQ9Lem5fGtwnyhpqVnqNpz VZ/1OUHn5GqKTZZS+RoEgYrxDIZbO1Sd5qbjliRhXRP8G+txx6uT1asReHmZD/+Ku6 vVEulaGvDNJlWv1AfNBF/4esy7AgA3SansaD2t8XWtVPSlhk2rjXIQ8D20i74U4Kni euYZf61oCUxrA== From: Yosry Ahmed To: Sean Christopherson Cc: Paolo Bonzini , kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Yosry Ahmed , Yosry Ahmed Subject: [PATCH 8/8] KVM: selftests: Trigger L2->L1 exits stress save+restore and #PF test Date: Mon, 18 May 2026 20:25:14 +0000 Message-ID: <20260518202514.2037078-9-yosry@kernel.org> X-Mailer: git-send-email 2.54.0.563.g4f69b47b94-goog In-Reply-To: <20260518202514.2037078-1-yosry@kernel.org> References: <20260518202514.2037078-1-yosry@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Yosry Ahmed Extend the testing coverage in L2 by injecting a #UD into the vCPU every other iteration during restore, and intercepting #UD from L1, essentially forcing an L2 -> L1 VM-Exit directly after save+restore. With this change, the test reliably reproduces the CR2 bug fixed by commit 5c247d08bc81 ("KVM: nSVM: Use vcpu->arch.cr2 when updating vmcb12 on nested #VMEXIT") -- at least on Milan, Genoa, and Turin CPUs. Signed-off-by: Yosry Ahmed --- .../kvm/x86/stress_save_restore_pf_test.c | 48 +++++++++++++++++-- 1 file changed, 43 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/kvm/x86/stress_save_restore_pf_test.c b/tools/testing/selftests/kvm/x86/stress_save_restore_pf_test.c index ec3d36d6e4846..e977d9786e392 100644 --- a/tools/testing/selftests/kvm/x86/stress_save_restore_pf_test.c +++ b/tools/testing/selftests/kvm/x86/stress_save_restore_pf_test.c @@ -115,8 +115,12 @@ static void l1_svm_code(struct svm_test_data *svm) generic_svm_setup(svm, guest_access_memory, &l2_guest_stack[L2_GUEST_STACK_SIZE]); - run_guest(svm->vmcb, svm->vmcb_gpa); - GUEST_ASSERT(false); + svm->vmcb->control.intercept_exceptions |= BIT(UD_VECTOR); + + while (1) { + run_guest(svm->vmcb, svm->vmcb_gpa); + GUEST_ASSERT_EQ(svm->vmcb->control.exit_code, (SVM_EXIT_EXCP_BASE + UD_VECTOR)); + } } static void l1_vmx_code(struct vmx_pages *vmx) @@ -127,13 +131,17 @@ static void l1_vmx_code(struct vmx_pages *vmx) GUEST_ASSERT(load_vmcs(vmx)); prepare_vmcs(vmx, guest_access_memory, &l2_guest_stack[L2_GUEST_STACK_SIZE]); - /* Ignore any #PF */ - GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, BIT(PF_VECTOR))); + /* Intercept UD, ignore any #PF */ + GUEST_ASSERT(!vmwrite(EXCEPTION_BITMAP, BIT(UD_VECTOR) | BIT(PF_VECTOR))); GUEST_ASSERT(!vmwrite(PAGE_FAULT_ERROR_CODE_MASK, 0)); GUEST_ASSERT(!vmwrite(PAGE_FAULT_ERROR_CODE_MATCH, -1)); GUEST_ASSERT(!vmlaunch()); - GUEST_ASSERT(false); + while (1) { + GUEST_ASSERT_EQ(vmreadz(VM_EXIT_REASON), EXIT_REASON_EXCEPTION_NMI); + GUEST_ASSERT_EQ(vmreadz(VM_EXIT_INTR_INFO) & 0xff, UD_VECTOR); + GUEST_ASSERT(!vmresume()); + } } static void l1_guest_code(void *test_data) @@ -171,6 +179,23 @@ static void vcpu_sigusr_ignore(void) sigaction(SIGUSR1, &sa, NULL); } +static bool vcpu_state_is_guest_mode(struct kvm_x86_state *state) +{ + return !!(state->nested.flags & KVM_STATE_NESTED_GUEST_MODE); +} + +static void vcpu_state_inject_ud(struct kvm_x86_state *state) +{ + if (state->events.exception.pending || state->events.exception.injected) + return; + + state->events.flags |= KVM_VCPUEVENT_VALID_PAYLOAD; + state->events.exception.pending = true; + state->events.exception.injected = false; + state->events.exception.nr = UD_VECTOR; + state->events.exception.has_error_code = false; +} + static bool parse_args_nested(int argc, char *argv[]) { bool nested = false; @@ -202,10 +227,13 @@ int main(int argc, char *argv[]) gva_t gva; gpa_t gpa; + TEST_REQUIRE(kvm_has_cap(KVM_CAP_EXCEPTION_PAYLOAD)); + nested = parse_args_nested(argc, argv); vm = vm_create_with_one_vcpu(&vcpu, nested ? l1_guest_code : guest_access_memory); vm_install_exception_handler(vm, PF_VECTOR, guest_pf_handler); + vm_enable_cap(vm, KVM_CAP_EXCEPTION_PAYLOAD, -2ul); if (nested) { TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_SVM) || kvm_cpu_has(X86_FEATURE_VMX)); @@ -264,8 +292,18 @@ int main(int argc, char *argv[]) state = vcpu_save_state(vcpu); + /* + * If the vCPU is in guest mode, inject a #UD to trigger an + * L2->L1 VM-Exit every other iteration. + */ + if (vcpu_state_is_guest_mode(state) && count % 2 == 0) { + TEST_ASSERT(nested, "Unexpected guest mode"); + vcpu_state_inject_ud(state); + } + kvm_vm_release(vm); vcpu = vm_recreate_with_one_vcpu(vm); + vm_enable_cap(vm, KVM_CAP_EXCEPTION_PAYLOAD, -2ul); vcpu_load_state(vcpu, state); kvm_x86_state_cleanup(state); -- 2.54.0.563.g4f69b47b94-goog