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From: Tom Lendacky <thomas.lendacky@amd.com>
To: Nikunj A Dadhania <nikunj@amd.com>,
	Borislav Petkov <bp@alien8.de>,
	Sean Christopherson <seanjc@google.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
	mingo@redhat.com, dave.hansen@linux.intel.com,
	santosh.shukla@amd.com
Subject: Re: [PATCH] x86/sev: Improve handling of writes to intercepted GUEST_TSC_FREQ
Date: Tue, 15 Jul 2025 07:47:12 -0500	[thread overview]
Message-ID: <e61ab0eb-816d-dc5d-dde5-e305a27705b2@amd.com> (raw)
In-Reply-To: <85ecuhx1eh.fsf@amd.com>

On 7/15/25 04:13, Nikunj A Dadhania wrote:
> Borislav Petkov <bp@alien8.de> writes:
> 
>> On Mon, Jul 14, 2025 at 09:36:04AM -0700, Sean Christopherson wrote:
>>> Or as Tom suggested, return ES_EXCEPTION and let the kernel's normal machinery
>>> WARN on the bad WRMSR.
>>
>> Ack.
> 
> That will panic the SNP guest instead of #GP:
> 
> root@ubuntu:~# wrmsr 0xc0010134 0
> [   20.804335] ------------[ cut here ]------------
> [   20.804336] WARNING: arch/x86/coco/sev/vc-handle.c:383 at vc_handle_exitcode.part.0+0xc1b/0x1090, CPU#0: wrmsr/607
> ...
> [   20.804507] SEV: Unsupported exception in #VC instruction emulation - can't continue
> [   20.804508] ------------[ cut here ]------------
> [   20.804508] kernel BUG at arch/x86/coco/sev/vc-handle.c:123!
> [   20.804514] Oops: invalid opcode: 0000 [#1] SMP NOPTI

Did you fill in the context with the #GP, i.e., ctxt->fi.vector and
ctxt->fi.error_code?

Thanks,
Tom

> 
> Regards,
> Nikunj

  parent reply	other threads:[~2025-07-15 12:47 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-07-11  4:12 [PATCH] x86/sev: Improve handling of writes to intercepted GUEST_TSC_FREQ Nikunj A Dadhania
2025-07-14 10:44 ` Borislav Petkov
2025-07-14 14:24   ` Sean Christopherson
2025-07-14 14:59     ` Tom Lendacky
2025-07-14 15:17       ` Sean Christopherson
2025-07-14 16:16         ` Borislav Petkov
2025-07-14 16:36           ` Sean Christopherson
2025-07-15  8:37             ` Nikunj A Dadhania
2025-07-15  8:43               ` Borislav Petkov
2025-07-15  8:58                 ` Nikunj A Dadhania
2025-07-15  8:38             ` Borislav Petkov
2025-07-15  9:13               ` Nikunj A Dadhania
2025-07-15  9:44                 ` Borislav Petkov
2025-07-15 12:47                 ` Tom Lendacky [this message]
2025-07-16  6:09                   ` Nikunj A Dadhania

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