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From: Sean Christopherson <sean.j.christopherson@intel.com>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Radim Krčmář" <rkrcmar@redhat.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 08/16] KVM: x86/mmu: Incorporate guest's page level into max level for shadow MMU
Date: Fri,  6 Dec 2019 15:57:21 -0800	[thread overview]
Message-ID: <20191206235729.29263-9-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20191206235729.29263-1-sean.j.christopherson@intel.com>

Restrict the max level for a shadow page based on the guest's level
instead of capping the level after the fact for host-mapped huge pages,
e.g. hugetlbfs pages.  Explicitly capping the max level using the guest
mapping level also eliminates FNAME(page_fault)'s subtle dependency on
THP only supporting 2mb pages.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
 arch/x86/kvm/mmu/paging_tmpl.h | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 1938a6e4e631..7d57ec576df0 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -773,7 +773,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
 	struct guest_walker walker;
 	int r;
 	kvm_pfn_t pfn;
-	int level = PT_PAGE_TABLE_LEVEL;
+	int level;
 	unsigned long mmu_seq;
 	bool map_writable, is_self_change_mapping;
 	bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
@@ -818,18 +818,14 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
 	is_self_change_mapping = FNAME(is_self_change_mapping)(vcpu,
 	      &walker, user_fault, &vcpu->arch.write_fault_to_shadow_pgtable);
 
-	max_level = lpage_disallowed ? PT_PAGE_TABLE_LEVEL :
-				       PT_MAX_HUGEPAGE_LEVEL;
-
-	if (walker.level >= PT_DIRECTORY_LEVEL && !is_self_change_mapping) {
-		level = mapping_level(vcpu, walker.gfn, &max_level);
-		if (likely(max_level > PT_DIRECTORY_LEVEL)) {
-			level = min(walker.level, level);
-			walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
-		}
-	} else {
+	if (lpage_disallowed || is_self_change_mapping)
 		max_level = PT_PAGE_TABLE_LEVEL;
-	}
+	else
+		max_level = walker.level;
+
+	level = mapping_level(vcpu, walker.gfn, &max_level);
+	if (level > PT_PAGE_TABLE_LEVEL)
+		walker.gfn = walker.gfn & ~(KVM_PAGES_PER_HPAGE(level) - 1);
 
 	mmu_seq = vcpu->kvm->mmu_notifier_seq;
 	smp_rmb();
-- 
2.24.0


  parent reply	other threads:[~2019-12-06 23:57 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-12-06 23:57 [PATCH 00/16] KVM: x86: MMU page fault clean-up Sean Christopherson
2019-12-06 23:57 ` [PATCH 01/16] KVM: x86: Use gpa_t for cr2/gpa to fix TDP support on 32-bit KVM Sean Christopherson
2019-12-06 23:57 ` [PATCH 02/16] KVM: x86/mmu: Move definition of make_mmu_pages_available() up Sean Christopherson
2019-12-06 23:57 ` [PATCH 03/16] KVM: x86/mmu: Fold nonpaging_map() into nonpaging_page_fault() Sean Christopherson
2019-12-06 23:57 ` [PATCH 04/16] KVM: x86/mmu: Move nonpaging_page_fault() below try_async_pf() Sean Christopherson
2019-12-06 23:57 ` [PATCH 05/16] KVM: x86/mmu: Refactor handling of cache consistency with TDP Sean Christopherson
2019-12-06 23:57 ` [PATCH 06/16] KVM: x86/mmu: Refactor the per-slot level calculation in mapping_level() Sean Christopherson
2019-12-06 23:57 ` [PATCH 07/16] KVM: x86/mmu: Refactor handling of forced 4k pages in page faults Sean Christopherson
2019-12-06 23:57 ` Sean Christopherson [this message]
2019-12-06 23:57 ` [PATCH 09/16] KVM: x86/mmu: Persist gfn_lpage_is_disallowed() to max_level Sean Christopherson
2019-12-06 23:57 ` [PATCH 10/16] KVM: x86/mmu: Rename lpage_disallowed to account_disallowed_nx_lpage Sean Christopherson
2019-12-06 23:57 ` [PATCH 11/16] KVM: x86/mmu: Consolidate tdp_page_fault() and nonpaging_page_fault() Sean Christopherson
2019-12-06 23:57 ` [PATCH 12/16] KVM: x86/mmu: Move transparent_hugepage_adjust() above __direct_map() Sean Christopherson
2019-12-06 23:57 ` [PATCH 13/16] KVM: x86/mmu: Move calls to thp_adjust() down a level Sean Christopherson
2019-12-06 23:57 ` [PATCH 14/16] KVM: x86/mmu: Move root_hpa validity checks to top of page fault handler Sean Christopherson
2019-12-06 23:57 ` [PATCH 15/16] KVM: x86/mmu: WARN on an invalid root_hpa Sean Christopherson
2019-12-06 23:57 ` [PATCH 16/16] KVM: x86/mmu: WARN if root_hpa is invalid when handling a page fault Sean Christopherson
2019-12-09 15:31 ` [PATCH 00/16] KVM: x86: MMU page fault clean-up Paolo Bonzini

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