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From: Manali Shukla <manali.shukla@amd.com>
To: <kvm@vger.kernel.org>, <linux-kselftest@vger.kernel.org>
Cc: <pbonzini@redhat.com>, <seanjc@google.com>, <shuah@kernel.org>,
	<nikunj@amd.com>, <thomas.lendacky@amd.com>,
	<vkuznets@redhat.com>, <manali.shukla@amd.com>, <bp@alien8.de>,
	<babu.moger@amd.com>
Subject: [RFC PATCH v2 4/5] KVM: X86: Add documentation about behavioral difference for KVM_EXIT_BUS_LOCK
Date: Tue, 1 Oct 2024 06:34:12 +0000	[thread overview]
Message-ID: <20241001063413.687787-5-manali.shukla@amd.com> (raw)
In-Reply-To: <20241001063413.687787-1-manali.shukla@amd.com>

Add a note about behavioral difference for KVM_EXIT_X86_BUS_LOCK
between AMD CPUs and Intel CPUs in KVM_CAP_X86_BUS_LOCK_EXIT
capability documentation.

Signed-off-by: Manali Shukla <manali.shukla@amd.com>
---
 Documentation/virt/kvm/api.rst | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index b3be87489108..536010e1df1d 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -7869,6 +7869,11 @@ Note! Detected bus locks may be coincident with other exits to userspace, i.e.
 KVM_RUN_X86_BUS_LOCK should be checked regardless of the primary exit reason if
 userspace wants to take action on all detected bus locks.
 
+Note! In KVM on AMD CPUs, the bus lock exit to user space occurs with RIP
+pointing at the offending instruction. In contrast, in KVM on Intel CPUs, the
+RIP points to the instruction right after the guilty one after the bus lock
+exit to user space.
+
 7.23 KVM_CAP_PPC_DAWR1
 ----------------------
 
-- 
2.34.1


  parent reply	other threads:[~2024-10-01  6:34 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-10-01  6:34 [RFC PATCH v2 0/5] Add support for the Bus Lock Threshold Manali Shukla
2024-10-01  6:34 ` [RFC PATCH v2 1/5] x86/cpu: Add virt tag in /proc/cpuinfo Manali Shukla
2024-10-01 16:41   ` Sean Christopherson
2024-10-03 11:05     ` Manali Shukla
2024-10-01  6:34 ` [RFC PATCH v2 2/5] x86/cpufeatures: Add CPUID feature bit for the Bus Lock Threshold Manali Shukla
2024-10-01  6:34 ` [RFC PATCH v2 3/5] KVM: SVM: Enable Bus lock threshold exit Manali Shukla
2024-10-01 13:43   ` Tom Lendacky
2024-10-03 11:08     ` Manali Shukla
2024-10-01  6:34 ` Manali Shukla [this message]
2024-10-01  6:34 ` [RFC PATCH v2 5/5] KVM: selftests: Add bus lock exit test Manali Shukla

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