From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org, Junaid Shahid <junaids@google.com>,
Wanpeng Li <wanpengli@tencent.com>,
kvm@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
Peter Shier <pshier@google.com>,
linux-mips@vger.kernel.org,
Sean Christopherson <sean.j.christopherson@intel.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
Ben Gardon <bgardon@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Peter Feiner <pfeiner@google.com>,
kvmarm@lists.cs.columbia.edu, Jim Mattson <jmattson@google.com>
Subject: [PATCH v3 07/21] KVM: x86/mmu: Topup memory caches after walking GVA->GPA
Date: Thu, 2 Jul 2020 19:35:31 -0700 [thread overview]
Message-ID: <20200703023545.8771-8-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200703023545.8771-1-sean.j.christopherson@intel.com>
Topup memory caches after walking the GVA->GPA translation during a
shadow page fault, there is no need to ensure the caches are full when
walking the GVA. As of commit f5a1e9f89504f ("KVM: MMU: remove call
to kvm_mmu_pte_write from walk_addr"), the FNAME(walk_addr) flow no
longer add rmaps via kvm_mmu_pte_write().
This avoids allocating memory in the case that the GVA is unmapped in
the guest, and also provides a paper trail of why/when the memory caches
need to be filled.
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/paging_tmpl.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 58234bfaca07..451d7aa7d959 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -788,10 +788,6 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
- r = mmu_topup_memory_caches(vcpu);
- if (r)
- return r;
-
/*
* If PFEC.RSVD is set, this is a shadow page fault.
* The bit needs to be cleared before walking guest page tables.
@@ -819,6 +815,10 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
return RET_PF_EMULATE;
}
+ r = mmu_topup_memory_caches(vcpu);
+ if (r)
+ return r;
+
vcpu->arch.write_fault_to_shadow_pgtable = false;
is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu,
--
2.26.0
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next prev parent reply other threads:[~2020-07-03 2:36 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 2:35 [PATCH v3 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 01/21] KVM: x86/mmu: Track the associated kmem_cache in the MMU caches Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 02/21] KVM: x86/mmu: Consolidate "page" variant of memory cache helpers Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 03/21] KVM: x86/mmu: Use consistent "mc" name for kvm_mmu_memory_cache locals Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 04/21] KVM: x86/mmu: Remove superfluous gotos from mmu_topup_memory_caches() Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 05/21] KVM: x86/mmu: Try to avoid crashing KVM if a MMU memory cache is empty Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 06/21] KVM: x86/mmu: Move fast_page_fault() call above mmu_topup_memory_caches() Sean Christopherson
2020-07-03 2:35 ` Sean Christopherson [this message]
2020-07-03 2:35 ` [PATCH v3 08/21] KVM: x86/mmu: Clean up the gorilla math in mmu_topup_memory_caches() Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 09/21] KVM: x86/mmu: Separate the memory caches for shadow pages and gfn arrays Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 10/21] KVM: x86/mmu: Make __GFP_ZERO a property of the memory cache Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 11/21] KVM: x86/mmu: Zero allocate shadow pages (outside of mmu_lock) Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 12/21] KVM: x86/mmu: Skip filling the gfn cache for guaranteed direct MMU topups Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 13/21] KVM: x86/mmu: Prepend "kvm_" to memory cache helpers that will be global Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 14/21] KVM: Move x86's version of struct kvm_mmu_memory_cache to common code Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 15/21] KVM: Move x86's MMU memory cache helpers to common KVM code Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 16/21] KVM: arm64: Drop @max param from mmu_topup_memory_cache() Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 17/21] KVM: arm64: Use common code's approach for __GFP_ZERO with memory caches Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 18/21] KVM: arm64: Use common KVM implementation of MMU " Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 19/21] KVM: MIPS: Drop @max param from mmu_topup_memory_cache() Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 20/21] KVM: MIPS: Account pages used for GPA page tables Sean Christopherson
2020-07-03 2:35 ` [PATCH v3 21/21] KVM: MIPS: Use common KVM implementation of MMU memory caches Sean Christopherson
2020-07-09 12:14 ` [PATCH v3 00/21] KVM: Cleanup and unify kvm_mmu_memory_cache usage Paolo Bonzini
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