From: Yosry Ahmed <yosry.ahmed@linux.dev>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Ken Hofsass <hofsass@google.com>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Yosry Ahmed <yosry.ahmed@linux.dev>
Subject: [PATCH 3/3] KVM: selftests: Verify CR3 in debug_regs
Date: Fri, 21 Nov 2025 19:32:04 +0000 [thread overview]
Message-ID: <20251121193204.952988-4-yosry.ahmed@linux.dev> (raw)
In-Reply-To: <20251121193204.952988-1-yosry.ahmed@linux.dev>
If KVM_CAP_X86_GUEST_DEBUG_CR3 is set, check that the value of CR3 in
struct kvm_run on KVM_EXIT_DEBUG matches that returned by KVM_GET_SREGS.
Signed-off-by: Yosry Ahmed <yosry.ahmed@linux.dev>
---
tools/testing/selftests/kvm/x86/debug_regs.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/x86/debug_regs.c b/tools/testing/selftests/kvm/x86/debug_regs.c
index 563e52217cdd..ecad92789182 100644
--- a/tools/testing/selftests/kvm/x86/debug_regs.c
+++ b/tools/testing/selftests/kvm/x86/debug_regs.c
@@ -80,8 +80,9 @@ static void vcpu_skip_insn(struct kvm_vcpu *vcpu, int insn_len)
int main(void)
{
+ unsigned long long target_dr6, target_rip, target_cr3;
struct kvm_guest_debug debug;
- unsigned long long target_dr6, target_rip;
+ struct kvm_sregs sregs;
struct kvm_vcpu *vcpu;
struct kvm_run *run;
struct kvm_vm *vm;
@@ -103,6 +104,14 @@ int main(void)
vm = vm_create_with_one_vcpu(&vcpu, guest_code);
run = vcpu->run;
+ if (kvm_has_cap(KVM_CAP_X86_GUEST_DEBUG_CR3)) {
+ pr_info("Debug info includes guest CR3\n");
+ vcpu_sregs_get(vcpu, &sregs);
+ target_cr3 = sregs.cr3;
+ } else {
+ target_cr3 = 0;
+ }
+
/* Test software BPs - int3 */
pr_info("Testing INT3\n");
memset(&debug, 0, sizeof(debug));
@@ -112,6 +121,7 @@ int main(void)
TEST_ASSERT_EQ(run->exit_reason, KVM_EXIT_DEBUG);
TEST_ASSERT_EQ(run->debug.arch.exception, BP_VECTOR);
TEST_ASSERT_EQ(run->debug.arch.pc, CAST_TO_RIP(sw_bp));
+ TEST_ASSERT_EQ(run->debug.arch.cr3, target_cr3);
vcpu_skip_insn(vcpu, 1);
/* Test instruction HW BP over DR[0-3] */
@@ -128,6 +138,7 @@ int main(void)
TEST_ASSERT_EQ(run->debug.arch.exception, DB_VECTOR);
TEST_ASSERT_EQ(run->debug.arch.pc, CAST_TO_RIP(hw_bp));
TEST_ASSERT_EQ(run->debug.arch.dr6, target_dr6);
+ TEST_ASSERT_EQ(run->debug.arch.cr3, target_cr3);
}
/* Skip "nop" */
vcpu_skip_insn(vcpu, 1);
@@ -147,6 +158,7 @@ int main(void)
TEST_ASSERT_EQ(run->debug.arch.exception, DB_VECTOR);
TEST_ASSERT_EQ(run->debug.arch.pc, CAST_TO_RIP(write_data));
TEST_ASSERT_EQ(run->debug.arch.dr6, target_dr6);
+ TEST_ASSERT_EQ(run->debug.arch.cr3, target_cr3);
/* Rollback the 4-bytes "mov" */
vcpu_skip_insn(vcpu, -7);
}
@@ -169,6 +181,7 @@ int main(void)
TEST_ASSERT_EQ(run->debug.arch.exception, DB_VECTOR);
TEST_ASSERT_EQ(run->debug.arch.pc, target_rip);
TEST_ASSERT_EQ(run->debug.arch.dr6, target_dr6);
+ TEST_ASSERT_EQ(run->debug.arch.cr3, target_cr3);
}
/* Finally test global disable */
@@ -183,6 +196,7 @@ int main(void)
TEST_ASSERT_EQ(run->debug.arch.exception, DB_VECTOR);
TEST_ASSERT_EQ(run->debug.arch.pc, CAST_TO_RIP(bd_start));
TEST_ASSERT_EQ(run->debug.arch.dr6, target_dr6);
+ TEST_ASSERT_EQ(run->debug.arch.cr3, target_cr3);
/* Disable all debug controls, run to the end */
memset(&debug, 0, sizeof(debug));
--
2.52.0.rc2.455.g230fcf2819-goog
prev parent reply other threads:[~2025-11-21 19:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-21 19:32 [PATCH 0/3] KVM: x86: Accelerate reading CR3 for guest debug Yosry Ahmed
2025-11-21 19:32 ` [PATCH 1/3] KVM: x86: Add CR3 to guest debug info Yosry Ahmed
2025-11-21 21:01 ` Sean Christopherson
2025-11-21 23:12 ` Yosry Ahmed
2025-11-24 14:45 ` Sean Christopherson
2025-11-24 15:35 ` Yosry Ahmed
2025-11-21 19:32 ` [PATCH 2/3] KVM: selftests: Use TEST_ASSERT_EQ() in debug_regs Yosry Ahmed
2025-11-21 19:32 ` Yosry Ahmed [this message]
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