Re: [PATCH 1/3] KVM: x86/mmu: Fix return value in tdp_mmu_map_handle_target_level()

From: Kai Huang <kai.huang@intel.com>
To: Ben Gardon <bgardon@google.com>, Sean Christopherson <seanjc@google.com>
Cc: kvm <kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 1/3] KVM: x86/mmu: Fix return value in tdp_mmu_map_handle_target_level()
Date: Thu, 06 May 2021 13:56:38 +1200	[thread overview]
Message-ID: <c96a3fc259726a52bbc18ccc5bb1b06d58216dee.camel@intel.com> (raw)
In-Reply-To: <CANgfPd_s1jrAaRRPtC=VUbeL=GfqWPncPx3RVG=+mK3fCiuiKQ@mail.gmail.com>

On Wed, 2021-05-05 at 09:04 -0700, Ben Gardon wrote:
> On Wed, May 5, 2021 at 9:00 AM Sean Christopherson <seanjc@google.com> wrote:
> > 
> > On Wed, May 05, 2021, Kai Huang wrote:
> > > Currently tdp_mmu_map_handle_target_level() returns 0, which is
> > > RET_PF_RETRY, when page fault is actually fixed.  This makes
> > > kvm_tdp_mmu_map() also return RET_PF_RETRY in this case, instead of
> > > RET_PF_FIXED.  Fix by initializing ret to RET_PF_FIXED.
> > 
> > Probably worth adding a blurb to call out that the bad return value is benign
> > since kvm_mmu_page_fault() resumes the guest on RET_PF_RETRY or RET_PF_FIXED.
> > And for good measure, a Fixes without stable@.
> > 
> >   Fixes: bb18842e2111 ("kvm: x86/mmu: Add TDP MMU PF handler")
> > 
> > Reviewed-by: Sean Christopherson <seanjc@google.com>
> 
> Haha I was just about to add the same two comments. Besides those,
> this patch looks good to me as well.
> 
> Reviewed-by: Ben Gardon <bgardon@google.com>
> 
> 

Thanks Sean and Ben. I'll add Sean's suggestion to commit message, and add a Fixes:...