From: Paolo Bonzini <pbonzini@redhat.com>
To: David Matlack <dmatlack@google.com>
Cc: kernel test robot <lkp@intel.com>,
kvm@vger.kernel.org, kbuild-all@lists.01.org,
Ben Gardon <bgardon@google.com>, Joerg Roedel <joro@8bytes.org>,
Jim Mattson <jmattson@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Junaid Shahid <junaids@google.com>
Subject: Re: [PATCH 2/4] KVM: x86/mmu: Remove redundant is_tdp_mmu_enabled check
Date: Fri, 18 Jun 2021 18:55:58 +0200 [thread overview]
Message-ID: <27d5b8eb-1f17-d981-064c-dedae18b6290@redhat.com> (raw)
In-Reply-To: <YMzOLu2OYn8GC/WD@google.com>
On 18/06/21 18:47, David Matlack wrote:
> On Fri, Jun 18, 2021 at 12:42:56PM +0200, Paolo Bonzini wrote:
>> On 18/06/21 09:17, kernel test robot wrote:
>>> ld: arch/x86/kvm/mmu/mmu.o: in function `get_mmio_spte':
>>>>> arch/x86/kvm/mmu/mmu.c:3612: undefined reference to `kvm_tdp_mmu_get_walk'
>>> ld: arch/x86/kvm/mmu/mmu.o: in function `direct_page_fault':
>>>>> arch/x86/kvm/mmu/mmu.c:3830: undefined reference to `kvm_tdp_mmu_map'
>>
>> Turns out sometimes is_tdp_mmu_root is not inlined after this patch.
>> Fixed thusly:
>
> Thanks for the fix. I guess after I removed the is_tdp_mmu_enabled()
> check the compiler couldn't determine what is_tdp_mmu_root() would
> return on 32-bit builds anymore.
It still could, but only as long as is_tdp_mmu_root was inlined. Your
patch caused the final "return false" to only appear after a few WARN_ON
checks that obviously can't be removed, and therefore tipped the balance
towards not inlining it!
Paolo
WARNING: multiple messages have this Message-ID (diff)
From: Paolo Bonzini <pbonzini@redhat.com>
To: kbuild-all@lists.01.org
Subject: Re: [PATCH 2/4] KVM: x86/mmu: Remove redundant is_tdp_mmu_enabled check
Date: Fri, 18 Jun 2021 18:55:58 +0200 [thread overview]
Message-ID: <27d5b8eb-1f17-d981-064c-dedae18b6290@redhat.com> (raw)
In-Reply-To: <YMzOLu2OYn8GC/WD@google.com>
[-- Attachment #1: Type: text/plain, Size: 989 bytes --]
On 18/06/21 18:47, David Matlack wrote:
> On Fri, Jun 18, 2021 at 12:42:56PM +0200, Paolo Bonzini wrote:
>> On 18/06/21 09:17, kernel test robot wrote:
>>> ld: arch/x86/kvm/mmu/mmu.o: in function `get_mmio_spte':
>>>>> arch/x86/kvm/mmu/mmu.c:3612: undefined reference to `kvm_tdp_mmu_get_walk'
>>> ld: arch/x86/kvm/mmu/mmu.o: in function `direct_page_fault':
>>>>> arch/x86/kvm/mmu/mmu.c:3830: undefined reference to `kvm_tdp_mmu_map'
>>
>> Turns out sometimes is_tdp_mmu_root is not inlined after this patch.
>> Fixed thusly:
>
> Thanks for the fix. I guess after I removed the is_tdp_mmu_enabled()
> check the compiler couldn't determine what is_tdp_mmu_root() would
> return on 32-bit builds anymore.
It still could, but only as long as is_tdp_mmu_root was inlined. Your
patch caused the final "return false" to only appear after a few WARN_ON
checks that obviously can't be removed, and therefore tipped the balance
towards not inlining it!
Paolo
next prev parent reply other threads:[~2021-06-18 16:56 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-17 23:19 [PATCH 0/5] KVM: x86/mmu: Clean up is_tdp_mmu_root and root_hpa checks David Matlack
2021-06-17 23:19 ` [PATCH 1/4] KVM: x86/mmu: Remove redundant is_tdp_mmu_root check David Matlack
2021-06-17 23:19 ` [PATCH 2/4] KVM: x86/mmu: Remove redundant is_tdp_mmu_enabled check David Matlack
2021-06-18 7:17 ` kernel test robot
2021-06-18 7:17 ` kernel test robot
2021-06-18 10:42 ` Paolo Bonzini
2021-06-18 10:42 ` Paolo Bonzini
2021-06-18 16:47 ` David Matlack
2021-06-18 16:47 ` David Matlack
2021-06-18 16:55 ` Paolo Bonzini [this message]
2021-06-18 16:55 ` Paolo Bonzini
2021-06-17 23:19 ` [PATCH 3/4] KVM: x86/mmu: Refactor is_tdp_mmu_root into is_tdp_mmu David Matlack
2021-06-17 23:19 ` [PATCH 4/4] KVM: x86/mmu: Remove redundant root_hpa checks David Matlack
2021-06-18 10:45 ` [PATCH 0/5] KVM: x86/mmu: Clean up is_tdp_mmu_root and " Paolo Bonzini
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