linux-kernel - Re: [PATCH RESEND v4 00/23] SMM emulation and interrupt shadow fixes

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Message-ID: <Y1xaz4pkH2FYSYvA@google.com>
Date:   Fri, 28 Oct 2022 22:42:23 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Maxim Levitsky <mlevitsk@...hat.com>, kvm@...r.kernel.org,
        Thomas Gleixner <tglx@...utronix.de>,
        Yang Zhong <yang.zhong@...el.com>, x86@...nel.org,
        Jim Mattson <jmattson@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Shuah Khan <shuah@...nel.org>,
        Guang Zeng <guang.zeng@...el.com>,
        Joerg Roedel <joro@...tes.org>, linux-kernel@...r.kernel.org,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        linux-kselftest@...r.kernel.org, Kees Cook <keescook@...omium.org>,
        "H. Peter Anvin" <hpa@...or.com>, Wei Wang <wei.w.wang@...el.com>,
        Borislav Petkov <bp@...en8.de>
Subject: Re: [PATCH RESEND v4 00/23] SMM emulation and interrupt shadow fixes

On Fri, Oct 28, 2022, Paolo Bonzini wrote:
> On 10/27/22 19:06, Maxim Levitsky wrote:
> > On Thu, 2022-10-27 at 18:49 +0200, Paolo Bonzini wrote:
> > > On 10/25/22 14:47, Maxim Levitsky wrote:
> > > > This patch series is a result of long debug work to find out why
> > > > sometimes guests with win11 secure boot
> > > > were failing during boot.
> > > > 
> > > > During writing a unit test I found another bug, turns out
> > > > that on rsm emulation, if the rsm instruction was done in real
> > > > or 32 bit mode, KVM would truncate the restored RIP to 32 bit.
> > > > 
> > > > I also refactored the way we write SMRAM so it is easier
> > > > now to understand what is going on.
> > > > 
> > > > The main bug in this series which I fixed is that we
> > > > allowed #SMI to happen during the STI interrupt shadow,
> > > > and we did nothing to both reset it on #SMI handler
> > > > entry and restore it on RSM.
> > > 
> > > I have now sent out the final/new version of the first 8 patches and
> > > will review these tomorrow.  Thanks for your patience. :)
> > > 
> > > Paolo
> > > 
> > Thank you very much!!
> 
> Queued, thanks.  Note that some emulator patches should go in stable
> releases so I have reordered them in front.

Can you fix patch 04 (also patch 04 in your series[*]) before pushing to kvm/queue?
The unused variable breaks CONFIG_KVM_WERROR=y builds.

arch/x86/kvm/smm.c: In function ‘emulator_leave_smm’:
arch/x86/kvm/smm.c:567:33: error: unused variable ‘efer’ [-Werror=unused-variable]
  567 |         unsigned long cr0, cr4, efer;
      |                                 ^~~~
arch/x86/kvm/smm.c:567:28: error: unused variable ‘cr4’ [-Werror=unused-variable]
  567 |         unsigned long cr0, cr4, efer;
      |                      

[*] https://lore.kernel.org/all/Y1xNso2nYZkSSZ0T@google.com