From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: yoshikawa_takuya_b1@lab.ntt.co.jp,
guangrong.xiao@linux.intel.com, mtosatti@redhat.com
Subject: [PATCH 12/12] KVM: MMU: micro-optimize gpte_access
Date: Wed, 24 Feb 2016 14:17:53 +0100 [thread overview]
Message-ID: <1456319873-34182-13-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1456319873-34182-1-git-send-email-pbonzini@redhat.com>
Avoid AND-NOT, most x86 processor lack an instruction for it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/kvm/paging_tmpl.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 2e019b103249..3c77bdd443d9 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -189,8 +189,11 @@ static inline unsigned FNAME(gpte_access)(struct kvm_vcpu *vcpu, u64 gpte)
((gpte & VMX_EPT_EXECUTABLE_MASK) ? ACC_EXEC_MASK : 0) |
ACC_USER_MASK;
#else
- access = (gpte & (PT_WRITABLE_MASK | PT_USER_MASK)) | ACC_EXEC_MASK;
- access &= ~(gpte >> PT64_NX_SHIFT);
+ BUILD_BUG_ON(ACC_EXEC_MASK != PT_PRESENT_MASK);
+ BUILD_BUG_ON(ACC_EXEC_MASK != 1);
+ access = gpte & (PT_WRITABLE_MASK | PT_USER_MASK | PT_PRESENT_MASK);
+ /* Combine NX with P (which is set here) to get ACC_EXEC_MASK. */
+ access ^= (gpte >> PT64_NX_SHIFT);
#endif
return access;
--
1.8.3.1
next prev parent reply other threads:[~2016-02-24 13:18 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-24 13:17 [PATCH 00/12] KVM: MMU: cleanup around kvm_sync_page, and a few micro-optimizations Paolo Bonzini
2016-02-24 13:17 ` [PATCH 01/12] KVM: MMU: Fix ubsan warnings Paolo Bonzini
2016-02-24 13:42 ` Mike Krinkin
2016-02-24 13:43 ` Paolo Bonzini
2016-02-24 13:17 ` [PATCH 02/12] KVM: MMU: check kvm_mmu_pages and mmu_page_path indices Paolo Bonzini
2016-02-24 13:17 ` [PATCH 03/12] KVM: MMU: introduce kvm_mmu_flush_or_zap Paolo Bonzini
2016-02-24 13:17 ` [PATCH 04/12] KVM: MMU: move TLB flush out of __kvm_sync_page Paolo Bonzini
2016-02-24 13:17 ` [PATCH 05/12] KVM: MMU: use kvm_sync_page in kvm_sync_pages Paolo Bonzini
2016-02-24 13:17 ` [PATCH 06/12] KVM: MMU: cleanup __kvm_sync_page and its callers Paolo Bonzini
2016-02-24 13:17 ` [PATCH 07/12] KVM: MMU: invert return value of FNAME(sync_page) and *kvm_sync_page* Paolo Bonzini
2016-02-24 13:17 ` [PATCH 08/12] KVM: MMU: move zap/flush to kvm_mmu_get_page Paolo Bonzini
2016-02-25 7:32 ` Xiao Guangrong
2016-02-25 8:48 ` Paolo Bonzini
2016-02-24 13:17 ` [PATCH 09/12] KVM: MMU: coalesce zapping page after mmu_sync_children Paolo Bonzini
2016-02-25 2:15 ` Takuya Yoshikawa
2016-02-25 7:35 ` Xiao Guangrong
2016-02-25 8:49 ` Paolo Bonzini
2016-02-25 9:10 ` Xiao Guangrong
2016-02-25 9:55 ` Paolo Bonzini
2016-02-25 8:46 ` Paolo Bonzini
2016-02-24 13:17 ` [PATCH 10/12] KVM: mark memory barrier with smp_mb__after_atomic Paolo Bonzini
2016-02-24 13:17 ` [PATCH 11/12] KVM: MMU: simplify last_pte_bitmap Paolo Bonzini
2016-02-24 13:17 ` Paolo Bonzini [this message]
2016-02-25 8:28 ` [PATCH 00/12] KVM: MMU: cleanup around kvm_sync_page, and a few micro-optimizations Xiao Guangrong
2016-02-25 8:49 ` Paolo Bonzini
2016-03-04 21:43 ` Paolo Bonzini
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