From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: peterx@redhat.com
Subject: [PATCH 9/9] KVM: VMX: pass correct DR6 for GD userspace exit
Date: Thu, 7 May 2020 07:50:11 -0400 [thread overview]
Message-ID: <20200507115011.494562-10-pbonzini@redhat.com> (raw)
In-Reply-To: <20200507115011.494562-1-pbonzini@redhat.com>
When KVM_EXIT_DEBUG is raised for the disabled-breakpoints case (DR7.GD),
DR6 was incorrectly copied from the value in the VM. Instead,
DR6.BD should be set in order to catch this case.
On AMD this does not need any special code because the processor triggers
a #DB exception that is intercepted. However, the testcase would fail
without the previous patch because both DR6.BS and DR6.BD would be set.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/vmx/vmx.c | 2 +-
.../testing/selftests/kvm/x86_64/debug_regs.c | 24 ++++++++++++++++++-
2 files changed, 24 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e2b71b0cdfce..e45cf89c5821 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4927,7 +4927,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
* guest debugging itself.
*/
if (vcpu->guest_debug & KVM_GUESTDBG_USE_HW_BP) {
- vcpu->run->debug.arch.dr6 = vcpu->arch.dr6;
+ vcpu->run->debug.arch.dr6 = DR6_BD | DR6_RTM | DR6_FIXED_1;
vcpu->run->debug.arch.dr7 = dr7;
vcpu->run->debug.arch.pc = kvm_get_linear_rip(vcpu);
vcpu->run->debug.arch.exception = DB_VECTOR;
diff --git a/tools/testing/selftests/kvm/x86_64/debug_regs.c b/tools/testing/selftests/kvm/x86_64/debug_regs.c
index 077f25d61d1a..8162c58a1234 100644
--- a/tools/testing/selftests/kvm/x86_64/debug_regs.c
+++ b/tools/testing/selftests/kvm/x86_64/debug_regs.c
@@ -11,10 +11,13 @@
#define VCPU_ID 0
+#define DR6_BD (1 << 13)
+#define DR7_GD (1 << 13)
+
/* For testing data access debug BP */
uint32_t guest_value;
-extern unsigned char sw_bp, hw_bp, write_data, ss_start;
+extern unsigned char sw_bp, hw_bp, write_data, ss_start, bd_start;
static void guest_code(void)
{
@@ -43,6 +46,8 @@ static void guest_code(void)
"rdmsr\n\t"
: : : "rax", "ecx");
+ /* DR6.BD test */
+ asm volatile("bd_start: mov %%dr0, %%rax" : : : "rax");
GUEST_DONE();
}
@@ -165,6 +170,23 @@ int main(void)
target_dr6);
}
+ /* Finally test global disable */
+ CLEAR_DEBUG();
+ debug.control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_HW_BP;
+ debug.arch.debugreg[7] = 0x400 | DR7_GD;
+ APPLY_DEBUG();
+ vcpu_run(vm, VCPU_ID);
+ target_dr6 = 0xffff0ff0 | DR6_BD;
+ TEST_ASSERT(run->exit_reason == KVM_EXIT_DEBUG &&
+ run->debug.arch.exception == DB_VECTOR &&
+ run->debug.arch.pc == CAST_TO_RIP(bd_start) &&
+ run->debug.arch.dr6 == target_dr6,
+ "DR7.GD: exit %d exception %d rip 0x%llx "
+ "(should be 0x%llx) dr6 0x%llx (should be 0x%llx)",
+ run->exit_reason, run->debug.arch.exception,
+ run->debug.arch.pc, target_rip, run->debug.arch.dr6,
+ target_dr6);
+
/* Disable all debug controls, run to the end */
CLEAR_DEBUG();
APPLY_DEBUG();
--
2.18.2
next prev parent reply other threads:[~2020-05-07 11:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-07 11:50 [PATCH v2 0/9] KVM_SET_GUEST_DEBUG tests and fixes, DR accessors cleanups Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 1/9] KVM: X86: Declare KVM_CAP_SET_GUEST_DEBUG properly Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 2/9] KVM: x86: fix DR6 delivery for various cases of #DB injection Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 3/9] KVM: X86: Set RTM for DB_VECTOR too for KVM_EXIT_DEBUG Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 4/9] KVM: X86: Fix single-step with KVM_SET_GUEST_DEBUG Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 5/9] KVM: selftests: Add KVM_SET_GUEST_DEBUG test Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 6/9] KVM: nSVM: trap #DB and #BP to userspace if guest debugging is on Paolo Bonzini
2020-05-07 18:22 ` Peter Xu
2020-05-07 11:50 ` [PATCH v2 7/9] KVM: SVM: keep DR6 synchronized with vcpu->arch.dr6 Paolo Bonzini
2020-05-07 18:22 ` Peter Xu
2020-05-07 22:21 ` Paolo Bonzini
2020-05-07 11:50 ` [PATCH v2 8/9] KVM: x86, SVM: isolate vcpu->arch.dr6 from vmcb->save.dr6 Paolo Bonzini
2020-05-07 19:28 ` Peter Xu
2020-05-07 22:33 ` Paolo Bonzini
2020-05-08 15:32 ` Peter Xu
2020-05-09 13:28 ` Paolo Bonzini
2020-05-11 16:15 ` Peter Xu
2020-05-07 11:50 ` Paolo Bonzini [this message]
2020-05-07 16:18 ` [PATCH 9/9] KVM: VMX: pass correct DR6 for GD userspace exit Peter Xu
2020-05-07 16:21 ` Paolo Bonzini
2020-05-07 16:38 ` Peter Xu
2020-05-07 17:42 ` Paolo Bonzini
2020-05-07 18:05 ` Peter Xu
-- strict thread matches above, loose matches on Subject: below --
2020-05-06 11:10 [PATCH 0/9] KVM_SET_GUEST_DEBUG tests and fixes, DR accessors cleanups Paolo Bonzini
2020-05-06 11:10 ` [PATCH 9/9] KVM: VMX: pass correct DR6 for GD userspace exit Paolo Bonzini
2020-05-06 17:50 ` Peter Xu
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=20200507115011.494562-10-pbonzini@redhat.com \
--to=pbonzini@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=peterx@redhat.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;
as well as URLs for NNTP newsgroup(s).