Re: [PATCH v7 0/7] x86/cpu, kvm: Support AMD Automatic IBRS

From: Sean Christopherson <seanjc@google.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org, Kim Phillips <kim.phillips@amd.com>,
	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>,
	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>,
	Tom Lendacky <thomas.lendacky@amd.com>,
	Alexey Kardashevskiy <aik@amd.com>,
	linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v7 0/7] x86/cpu, kvm: Support AMD Automatic IBRS
Date: Fri, 20 Jan 2023 01:40:13 +0000	[thread overview]
Message-ID: <Y8nw/XLTpKhKbbdX@google.com> (raw)
In-Reply-To: <Y8aMiH74WFmVM5Rk@zn.tnic>

On Tue, Jan 17, 2023, Borislav Petkov wrote:
> On Mon, Jan 16, 2023 at 05:01:52PM -0600, Kim Phillips wrote:
> 
> > Kim Phillips (7):
> >   x86/cpu, kvm: Add support for cpuid leaf 80000021/EAX (FeatureExt2Eax)
> >   x86/cpu, kvm: Add the NO_NESTED_DATA_BP feature
> >   x86/cpu, kvm: Move the LFENCE_RDTSC / LFENCE always serializing
> >     feature
> >   x86/cpu, kvm: Add the Null Selector Clears Base feature
> >   x86/cpu, kvm: Add the SMM_CTL MSR not present feature
> >   x86/cpu: Support AMD Automatic IBRS
> >   x86/cpu, kvm: Propagate the AMD Automatic IBRS feature to the guest
> > 
> >  Documentation/admin-guide/hw-vuln/spectre.rst |  6 ++--
> >  .../admin-guide/kernel-parameters.txt         |  6 ++--
> >  arch/x86/include/asm/cpufeature.h             |  7 +++--
> >  arch/x86/include/asm/cpufeatures.h            | 11 +++++--
> >  arch/x86/include/asm/disabled-features.h      |  3 +-
> >  arch/x86/include/asm/msr-index.h              |  2 ++
> >  arch/x86/include/asm/required-features.h      |  3 +-
> >  arch/x86/kernel/cpu/amd.c                     |  2 +-
> >  arch/x86/kernel/cpu/bugs.c                    | 20 ++++++++-----
> >  arch/x86/kernel/cpu/common.c                  | 22 +++++++++-----
> >  arch/x86/kvm/cpuid.c                          | 30 +++++++------------
> >  arch/x86/kvm/reverse_cpuid.h                  |  1 +
> >  arch/x86/kvm/svm/svm.c                        |  3 ++
> >  arch/x86/kvm/x86.c                            |  3 ++
> >  14 files changed, 71 insertions(+), 48 deletions(-)
> 
> KVM folks,
> 
> I'm going to route this through the tip tree, along with the KVM bits.
> 
> Holler if we should do something else to avoid any potential conflicts.

Sorry, completely missed this.

There will be a minor conflict in KVM's reverse_cpuid, but it's trivial to resolve.
I don't anticipate any other conflicts, so taking this through tip does seem like
the best option.

If possible, a new version to fix the bisection issues in patches 2 and 3 would
be nice, but again it's not a big deal.  The breakage is very, very minor.