From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
Elena Reshetova <elena.reshetova@intel.com>,
Jun Nakajima <jun.nakajima@intel.com>,
x86@kernel.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86/tdx: Mark TSC reliable
Date: Fri, 25 Aug 2023 16:52:26 +0300 [thread overview]
Message-ID: <20230825135226.ikxvskplvppghwtz@box.shutemov.name> (raw)
In-Reply-To: <87bkewcufi.ffs@tglx>
On Thu, Aug 24, 2023 at 05:49:05PM +0200, Thomas Gleixner wrote:
> On Tue, Aug 08 2023 at 23:01, Kirill A. Shutemov wrote:
> > On Tue, Aug 08, 2023 at 10:13:05AM -0700, Dave Hansen wrote:
> >> I take it this is carved in stone in the TDX specs somewhere. A
> >> reference would be nice.
> >
> > TDX Module 1.0 spec:
> >
> > 5.3.5. Time Stamp Counter (TSC)
> >
> > TDX provides a trusted virtual TSC to the guest TDs. TSC value is
> > monotonously incrementing, starting from 0 on TD initialization by the
> > host VMM. The deviation between virtual TSC values read by each VCPU is
> > small.
>
> Nice weasel wording. What's the definition of "small"?
The newer spec says "Virtual TSC values are consistent among all the TD’s
VCPUs at the level supported by the CPU".
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2023-08-25 13:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-08-08 16:23 [PATCH] x86/tdx: Mark TSC reliable Kirill A. Shutemov
2023-08-08 17:13 ` Dave Hansen
2023-08-08 20:01 ` Kirill A. Shutemov
2023-08-09 5:44 ` Reshetova, Elena
2023-08-09 6:13 ` Kirill A. Shutemov
2023-08-22 23:39 ` Erdem Aktas
2023-08-24 15:49 ` Thomas Gleixner
2023-08-25 13:52 ` Kirill A. Shutemov [this message]
2023-08-25 17:09 ` Thomas Gleixner
2023-08-29 16:01 ` Nakajima, Jun
2023-08-30 7:33 ` Thomas Gleixner
2023-08-31 15:16 ` Nakajima, Jun
2023-08-24 19:31 ` Thomas Gleixner
2023-08-25 13:47 ` Kirill A. Shutemov
2023-08-25 15:16 ` Sean Christopherson
2023-09-07 17:25 ` Paolo Bonzini
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