From: Dave Hansen <dave.hansen@intel.com>
To: Xi Ruoyao <xry111@xry111.site>,
Dave Hansen <dave.hansen@linux.intel.com>,
Michael Kelley <mhklinux@outlook.com>,
Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Sean Christopherson <seanjc@google.com>,
Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [PATCH v6] x86/mm: Don't disable INVLPG if "incomplete Global INVLPG flushes" is fixed by microcode or the kernel is running in a hypervisor
Date: Thu, 11 Apr 2024 07:44:43 -0700 [thread overview]
Message-ID: <3ee70b6c-3399-43f9-8934-cb5a0e51f006@intel.com> (raw)
In-Reply-To: <20240411104822.6429-1-xry111@xry111.site>
On 4/11/24 03:48, Xi Ruoyao wrote:
> + /*
> + * The Intel errata claims: "this erratum does not apply in VMX
> + * non-root operation. It applies only when PCIDs are enabled
> + * and either in VMX root operation or outside VMX operation."
> + * So we are safe if we are surely running in a hypervisor.
> + */
When you revise this, could you please work to make this more succinct?
The Intel language on these things tends to be a bit flowery and is not
always well-suited for the kernel.
Also, saying that the erratum "claims" this casts doubt on it. That's
counterproductive. I believe the current documentation is correct. My
original ce0b15d11ad8 ("x86/mm: Avoid incomplete Global INVLPG flushes")
should have considered virtualized systems immune to this issue.
I agree that it sounds weird. It _is_ weird that systems running under
hypervisors aren't affected. But that's all it is: a weird bug. The
documentation is correct.
next prev parent reply other threads:[~2024-04-11 14:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-11 10:48 [PATCH v6] x86/mm: Don't disable INVLPG if "incomplete Global INVLPG flushes" is fixed by microcode or the kernel is running in a hypervisor Xi Ruoyao
2024-04-11 14:29 ` Sean Christopherson
2024-04-11 14:44 ` Dave Hansen [this message]
2024-04-11 14:48 ` Xi Ruoyao
2024-04-11 15:00 ` Andrew Cooper
2024-04-11 15:18 ` Dave Hansen
2024-04-11 15:43 ` Dave Hansen
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