From: Tom Lendacky <thomas.lendacky@amd.com>
To: Borislav Petkov <bp@alien8.de>, "Nikunj A. Dadhania" <nikunj@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
kvm@vger.kernel.org, mingo@redhat.com, tglx@linutronix.de,
dave.hansen@linux.intel.com, pgonda@google.com,
seanjc@google.com, pbonzini@redhat.com,
francescolavra.fl@gmail.com
Subject: Re: [PATCH v16 05/13] x86/sev: Add Secure TSC support for SNP guests
Date: Tue, 7 Jan 2025 12:53:26 -0600 [thread overview]
Message-ID: <32359d64-357b-2104-59e8-4d3339a2197c@amd.com> (raw)
In-Reply-To: <20250107123711.GEZ30f9_OzOcJSF10o@fat_crate.local>
On 1/7/25 06:37, Borislav Petkov wrote:
> On Tue, Jan 07, 2025 at 05:13:03PM +0530, Nikunj A. Dadhania wrote:
>>>> + case CC_ATTR_GUEST_SNP_SECURE_TSC:
>>>> + return (sev_status & MSR_AMD64_SEV_SNP_ENABLED) &&
>>>
>>> This is new here?
>>
>> Yes, this was suggested by Tom here [1]
>
> Either of you care to explain why this is needed?
>
>>>> + (sev_status & MSR_AMD64_SNP_SECURE_TSC);
>
> I would strongly assume that whatever sets MSR_AMD64_SNP_SECURE_TSC will have
> checked/set MSR_AMD64_SEV_SNP_ENABLED already.
Yes, but from a readability point of view this makes it perfectly clear
that Secure TSC is only for SNP guests.
It's not on a fast path, so I don't think it hurts anything by having
the extra check. But if you prefer the previous check, I'm ok with that.
Thanks,
Tom
>
next prev parent reply other threads:[~2025-01-07 18:53 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-06 12:46 [PATCH v16 00/13] " Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 01/13] virt: sev-guest: Remove is_vmpck_empty() helper Nikunj A Dadhania
2025-01-07 18:38 ` Tom Lendacky
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 02/13] virt: sev-guest: Replace GFP_KERNEL_ACCOUNT with GFP_KERNEL Nikunj A Dadhania
2025-01-07 18:40 ` Tom Lendacky
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 03/13] x86/sev: Carve out and export SNP guest messaging init routines Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 04/13] x86/sev: Relocate SNP guest messaging routines to common code Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 05/13] x86/sev: Add Secure TSC support for SNP guests Nikunj A Dadhania
2025-01-07 10:42 ` Borislav Petkov
2025-01-07 11:43 ` Nikunj A. Dadhania
2025-01-07 12:37 ` Borislav Petkov
2025-01-07 18:53 ` Tom Lendacky [this message]
2025-01-07 19:18 ` Borislav Petkov
2025-01-08 7:47 ` Nikunj A. Dadhania
2025-01-08 8:05 ` Borislav Petkov
2025-01-08 8:37 ` Nikunj A. Dadhania
2025-01-08 8:43 ` Borislav Petkov
2025-01-07 19:46 ` Tom Lendacky
2025-01-07 19:53 ` Borislav Petkov
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 06/13] x86/sev: Change TSC MSR behavior for Secure TSC enabled guests Nikunj A Dadhania
2025-01-07 20:09 ` Tom Lendacky
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 07/13] x86/sev: Prevent GUEST_TSC_FREQ MSR interception " Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 08/13] x86/sev: Prevent RDTSC/RDTSCP " Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] " tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 09/13] x86/sev: Mark Secure TSC as reliable clocksource Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] x86/sev: Mark the TSC in a secure TSC guest as reliable tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 10/13] x86/tsc: Switch Secure TSC guests away from kvm-clock Nikunj A Dadhania
2025-01-07 15:16 ` Borislav Petkov
2025-01-08 10:45 ` Nikunj A. Dadhania
2025-01-09 9:43 ` [tip: x86/sev] x86/tsc: Init the TSC for Secure TSC guests tip-bot2 for Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 11/13] x86/tsc: Upgrade TSC clocksource rating for guests Nikunj A Dadhania
2025-01-07 17:51 ` Borislav Petkov
2025-01-06 12:46 ` [PATCH v16 12/13] x86/tsc: Switch to native sched clock Nikunj A Dadhania
2025-01-07 19:37 ` Borislav Petkov
2025-01-08 5:20 ` Nikunj A. Dadhania
2025-01-08 8:22 ` Borislav Petkov
2025-01-08 8:34 ` Nikunj A. Dadhania
2025-01-08 10:20 ` Nikunj A. Dadhania
2025-01-08 14:00 ` Sean Christopherson
2025-01-08 15:34 ` Borislav Petkov
2025-01-08 17:02 ` Sean Christopherson
2025-01-08 19:53 ` Borislav Petkov
2025-01-09 6:32 ` Nikunj A. Dadhania
2025-01-15 21:37 ` Sean Christopherson
2025-01-16 16:25 ` Borislav Petkov
2025-01-16 16:56 ` Sean Christopherson
2025-01-17 20:28 ` Borislav Petkov
2025-01-17 20:59 ` Sean Christopherson
2025-01-21 11:32 ` Borislav Petkov
2025-01-21 3:59 ` Nikunj A. Dadhania
2025-01-28 5:41 ` Nikunj A Dadhania
2025-01-06 12:46 ` [PATCH v16 13/13] x86/sev: Allow Secure TSC feature for SNP guests Nikunj A Dadhania
2025-01-09 9:43 ` [tip: x86/sev] x86/sev: Add the " tip-bot2 for Nikunj A Dadhania
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=32359d64-357b-2104-59e8-4d3339a2197c@amd.com \
--to=thomas.lendacky@amd.com \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=francescolavra.fl@gmail.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=nikunj@amd.com \
--cc=pbonzini@redhat.com \
--cc=pgonda@google.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/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
Powered by JetHome