From: Kim Phillips <kim.phillips@amd.com>
To: Borislav Petkov <bp@alien8.de>
Cc: x86@kernel.org, Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
Joao Martins <joao.m.martins@oracle.com>,
Jonathan Corbet <corbet@lwn.net>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Thomas Gleixner <tglx@linutronix.de>,
David Woodhouse <dwmw@amazon.co.uk>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Juergen Gross <jgross@suse.com>,
Peter Zijlstra <peterz@infradead.org>,
Tony Luck <tony.luck@intel.com>, Babu Moger <Babu.Moger@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
kvm@vger.kernel.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] x86/cpufeatures: Add support for cpuid leaf 80000021/EAX (FeatureExt2Eax)
Date: Tue, 15 Nov 2022 17:10:50 -0600 [thread overview]
Message-ID: <c00b1a65-c885-c874-79cb-16011ac82eb3@amd.com> (raw)
In-Reply-To: <Y2WIy2A1RuQE/9SK@zn.tnic>
On 11/4/22 4:48 PM, Borislav Petkov wrote:
> On Fri, Nov 04, 2022 at 04:36:49PM -0500, Kim Phillips wrote:
>> AMD Zen4 processors advertise features in this leaf.
>> Add the leaf and its Automatic IBRS feature bit.
>>
>> Note: New whole leaf (vs a bit) due to propagation via KVM
>> later in this series.
>
> No, not a separate leaf - use scattered.c
> > For an example what to do for KVM, see
>
> https://lore.kernel.org/r/20221103025030.78371-1-jiaxi.chen@linux.intel.com
That adds features that are mutually exclusive between
kvm and the host kernel, unlike AUTOIBRS.
When trying to wire up a scattered host AUTOIBRS version up to
kvm, I couldn't get past all the reverse_cpuid_check()
BUILD_BUGs demanding exclusivity between h/w and "Linux"
(s/w) FEATUREs.
Is there an example of a scattered feature that gets both its
boot_cpu_has() and guest_cpuid_has() satisfied in the same build?
If not, I'll resubmit like this original submission - AUTOIBRS in
a separate h/w leaf.
Thanks,
Kim
next prev parent reply other threads:[~2022-11-15 23:11 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-04 21:36 [PATCH 0/3] x86/speculation: Support Automatic IBRS Kim Phillips
2022-11-04 21:36 ` [PATCH 1/3] x86/cpufeatures: Add support for cpuid leaf 80000021/EAX (FeatureExt2Eax) Kim Phillips
2022-11-04 21:48 ` Borislav Petkov
2022-11-15 23:10 ` Kim Phillips [this message]
2022-11-16 11:59 ` Borislav Petkov
2022-11-16 20:22 ` Sean Christopherson
2022-11-16 21:01 ` Borislav Petkov
2022-11-04 21:36 ` [PATCH 2/3] x86/speculation: Support Automatic IBRS Kim Phillips
2022-11-04 21:52 ` Borislav Petkov
2022-11-05 11:10 ` Peter Zijlstra
2022-11-07 22:39 ` Kim Phillips
2022-11-07 23:41 ` Dave Hansen
2022-11-08 8:06 ` Peter Zijlstra
2022-11-11 12:09 ` Borislav Petkov
2022-11-11 12:40 ` Thadeu Lima de Souza Cascardo
2022-11-12 0:46 ` Kim Phillips
2022-11-12 0:54 ` Jim Mattson
2022-11-05 11:39 ` David Laight
2022-11-07 22:40 ` Kim Phillips
2022-11-04 21:36 ` [PATCH 3/3] x86/speculation: Support Automatic IBRS under virtualization Kim Phillips
2022-11-04 22:00 ` Jim Mattson
2022-11-07 22:29 ` Kim Phillips
2022-11-07 22:42 ` Jim Mattson
2022-11-08 22:48 ` Kim Phillips
2022-11-08 22:59 ` Jim Mattson
2022-11-06 8:38 ` Paolo Bonzini
2022-11-04 22:06 ` [PATCH 0/3] x86/speculation: Support Automatic IBRS Dave Hansen
2022-11-07 22:43 ` Kim Phillips
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