From: Borislav Petkov <bp@alien8.de>
To: Yazen Ghannam <yazen.ghannam@amd.com>
Cc: "Luck, Tony" <tony.luck@intel.com>,
Smita Koralahalli <Smita.KoralahalliChannabasappa@amd.com>,
"x86@kernel.org" <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
James Morse <james.morse@arm.com>,
Robert Richter <rric@kernel.org>
Subject: Re: [PATCH] EDAC/mce_amd: Reduce unnecessary spew in dmesg if SMCA feature bit is not exposed
Date: Tue, 15 Jun 2021 19:25:57 +0200 [thread overview]
Message-ID: <YMjipVYQO93i46HJ@zn.tnic> (raw)
In-Reply-To: <20210615163221.GA2991@aus-x-yghannam.amd.com>
On Tue, Jun 15, 2021 at 12:32:21PM -0400, Yazen Ghannam wrote:
> Yes, I agree. I was a bit confused about the X86_FEATURE_HYPERVISOR
> thing, but I think I get it. This definitely looks simple to do.
Yeah, if you look at the qemu repo:
kvm_arch_get_supported_cpuid:
...
} else if (function == 1 && reg == R_ECX) {
/* We can set the hypervisor flag, even if KVM does not return it on
* GET_SUPPORTED_CPUID
*/
ret |= CPUID_EXT_HYPERVISOR;
so long story short, that thing is set by the HV and there's an
"agreement" of sorts and APM v3 even says so:
"CPUID Fn0000_0001_ECX Feature Identifiers
...
31: RAZ. Reserved for use by hypervisor to indicate guest status."
HTH.
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
prev parent reply other threads:[~2021-06-15 17:26 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-14 21:21 [PATCH] EDAC/mce_amd: Reduce unnecessary spew in dmesg if SMCA feature bit is not exposed Smita Koralahalli
2021-06-14 22:01 ` Borislav Petkov
2021-06-14 22:25 ` Luck, Tony
2021-06-15 9:16 ` Borislav Petkov
2021-06-15 15:08 ` Yazen Ghannam
2021-06-15 15:18 ` Borislav Petkov
2021-06-15 16:00 ` Yazen Ghannam
2021-06-15 16:11 ` Borislav Petkov
2021-06-15 16:32 ` Yazen Ghannam
2021-06-15 16:45 ` [PATCH] EDAC/Intel: Do not load EDAC driver when running as a guest Luck, Tony
2021-06-15 17:00 ` Borislav Petkov
2021-06-15 17:44 ` [PATCH v2] " Luck, Tony
2021-06-15 17:25 ` Borislav Petkov [this message]
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