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From: Ravi Bangoria <ravi.bangoria@amd.com>
To: Jim Mattson <jmattson@google.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,
	sandipan.das@amd.com, Ravi Bangoria <ravi.bangoria@amd.com>
Subject: Re: [PATCH 2/3] x86/bus_lock: Add support for AMD
Date: Tue, 7 May 2024 09:27:45 +0530	[thread overview]
Message-ID: <3685c15f-3485-53b0-7955-7931efaee960@amd.com> (raw)
In-Reply-To: <CALMp9eQzbNVJpuxp1orNswnyfKy=aFSPYFRnd3H7fbi0+NfDvw@mail.gmail.com>

On 06-May-24 9:54 PM, Jim Mattson wrote:
> On Sun, Apr 28, 2024 at 11:08 PM Ravi Bangoria <ravi.bangoria@amd.com> 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=304653
> 
> 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?

You are probably asking about "Bus Lock Threshold". Please see
"15.14.5 Bus Lock Threshold" in the same doc. fwiw, Bus Lock Threshold
is of fault style.

Thanks,
Ravi

  reply	other threads:[~2024-05-07  3:58 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-29  6:06 [PATCH 0/3] x86/cpu: Add Bus Lock Detect " Ravi Bangoria
2024-04-29  6:06 ` [PATCH 1/3] x86/split_lock: Move Split and Bus lock code to a dedicated file Ravi Bangoria
2024-05-06 12:58   ` Borislav Petkov
2024-05-07  4:07     ` Ravi Bangoria
2024-04-29  6:06 ` [PATCH 2/3] x86/bus_lock: Add support for AMD Ravi Bangoria
2024-05-06 16:05   ` Tom Lendacky
2024-05-07  4:08     ` Ravi Bangoria
2024-05-06 16:24   ` Jim Mattson
2024-05-07  3:57     ` Ravi Bangoria [this message]
2024-04-29  6:06 ` [PATCH 3/3] KVM SVM: Add Bus Lock Detect support Ravi Bangoria
2024-06-04  0:45   ` Sean Christopherson
2024-06-05 11:38     ` Ravi Bangoria
2024-06-05 15:08       ` Sean Christopherson
2024-06-05 16:14         ` Ravi Bangoria
2024-06-12  1:42           ` Sean Christopherson
2024-07-10  2:25             ` Ravi Bangoria
2024-07-10  4:15               ` Jim Mattson
2024-07-10 13:52                 ` Sean Christopherson
2024-07-11  8:51                   ` Ravi Bangoria

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