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From: Jim Mattson <jmattson@google.com>
Date: Mon, 6 May 2024 09:24:00 -0700
Message-ID: <CALMp9eQzbNVJpuxp1orNswnyfKy=aFSPYFRnd3H7fbi0+NfDvw@mail.gmail.com>
Subject: Re: [PATCH 2/3] x86/bus_lock: Add support for AMD
To: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, 
	dave.hansen@linux.intel.com, seanjc@google.com, pbonzini@redhat.com, 
	thomas.lendacky@amd.com, hpa@zytor.com, rmk+kernel@armlinux.org.uk, 
	peterz@infradead.org, james.morse@arm.com, lukas.bulwahn@gmail.com, 
	arjan@linux.intel.com, j.granados@samsung.com, sibs@chinatelecom.cn, 
	nik.borisov@suse.com, michael.roth@amd.com, nikunj.dadhania@amd.com, 
	babu.moger@amd.com, x86@kernel.org, kvm@vger.kernel.org, 
	linux-kernel@vger.kernel.org, santosh.shukla@amd.com, ananth.narayan@amd.com, 
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On Sun, Apr 28, 2024 at 11:08=E2=80=AFPM Ravi Bangoria <ravi.bangoria@amd.c=
om> wrote:
>
> Upcoming AMD uarch will support Bus Lock Detect (called Bus Lock Trap
> in AMD docs). Add support for the same in Linux. Bus Lock Detect is
> enumerated with cpuid CPUID Fn0000_0007_ECX_x0 bit [24 / BUSLOCKTRAP].
> It can be enabled through MSR_IA32_DEBUGCTLMSR. When enabled, hardware
> clears DR6[11] and raises a #DB exception on occurrence of Bus Lock if
> CPL > 0. More detail about the feature can be found in AMD APM[1].
>
> [1]: AMD64 Architecture Programmer's Manual Pub. 40332, Rev. 4.07 - June
>      2023, Vol 2, 13.1.3.6 Bus Lock Trap
>      https://bugzilla.kernel.org/attachment.cgi?id=3D304653

Is there any chance of getting something similar to Intel's "VMM
bus-lock detection," which causes a trap-style VM-exit on a bus lock
event?