From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, Michael Tsirkin <mst@redhat.com>,
Julia Suvorova <jsuvorov@redhat.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>,
x86@kernel.org
Subject: [PATCH RFC 4/5] KVM: x86: aggressively map PTEs in KVM_MEM_ALLONES slots
Date: Thu, 14 May 2020 20:05:39 +0200 [thread overview]
Message-ID: <20200514180540.52407-5-vkuznets@redhat.com> (raw)
In-Reply-To: <20200514180540.52407-1-vkuznets@redhat.com>
All PTEs in KVM_MEM_ALLONES slots point to the same read-only page
in KVM so instead of mapping each page upon first access we can map
everything aggressively.
Suggested-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
arch/x86/kvm/mmu/mmu.c | 20 ++++++++++++++++++--
arch/x86/kvm/mmu/paging_tmpl.h | 23 +++++++++++++++++++++--
2 files changed, 39 insertions(+), 4 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3db499df2dfc..e92ca9ed3ff5 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4154,8 +4154,24 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, gpa_t gpa, u32 error_code,
goto out_unlock;
if (make_mmu_pages_available(vcpu) < 0)
goto out_unlock;
- r = __direct_map(vcpu, gpa, write, map_writable, max_level, pfn,
- prefault, is_tdp && lpage_disallowed);
+
+ if (likely(!(slot->flags & KVM_MEM_ALLONES) || write)) {
+ r = __direct_map(vcpu, gpa, write, map_writable, max_level, pfn,
+ prefault, is_tdp && lpage_disallowed);
+ } else {
+ /*
+ * KVM_MEM_ALLONES are 4k only slots fully mapped to the same
+ * readonly 'allones' page, map all PTEs aggressively here.
+ */
+ for (gfn = slot->base_gfn; gfn < slot->base_gfn + slot->npages;
+ gfn++) {
+ r = __direct_map(vcpu, gfn << PAGE_SHIFT, write,
+ map_writable, max_level, pfn, prefault,
+ is_tdp && lpage_disallowed);
+ if (r)
+ break;
+ }
+ }
out_unlock:
spin_unlock(&vcpu->kvm->mmu_lock);
diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index 98e368788e8b..7bf0c48b858f 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -789,6 +789,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
bool lpage_disallowed = (error_code & PFERR_FETCH_MASK) &&
is_nx_huge_page_enabled();
int max_level;
+ gfn_t gfn;
pgprintk("%s: addr %lx err %x\n", __func__, addr, error_code);
@@ -873,8 +874,26 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gpa_t addr, u32 error_code,
kvm_mmu_audit(vcpu, AUDIT_PRE_PAGE_FAULT);
if (make_mmu_pages_available(vcpu) < 0)
goto out_unlock;
- r = FNAME(fetch)(vcpu, addr, &walker, write_fault, max_level, pfn,
- map_writable, prefault, lpage_disallowed);
+ if (likely(!(slot->flags & KVM_MEM_ALLONES) || write_fault)) {
+ r = FNAME(fetch)(vcpu, addr, &walker, write_fault, max_level,
+ pfn, map_writable, prefault, lpage_disallowed);
+ } else {
+ /*
+ * KVM_MEM_ALLONES are 4k only slots fully mapped to the same
+ * readonly 'allones' page, map all PTEs aggressively here.
+ */
+ for (gfn = slot->base_gfn; gfn < slot->base_gfn + slot->npages;
+ gfn++) {
+ walker.gfn = gfn;
+ r = FNAME(fetch)(vcpu, gfn << PAGE_SHIFT, &walker,
+ write_fault, max_level, pfn,
+ map_writable, prefault,
+ lpage_disallowed);
+ if (r)
+ break;
+ }
+ }
+
kvm_mmu_audit(vcpu, AUDIT_POST_PAGE_FAULT);
out_unlock:
--
2.25.4
next prev parent reply other threads:[~2020-05-14 18:06 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-14 18:05 [PATCH RFC 0/5] KVM: x86: KVM_MEM_ALLONES memory Vitaly Kuznetsov
2020-05-14 18:05 ` [PATCH RFC 1/5] KVM: rename labels in kvm_init() Vitaly Kuznetsov
2020-05-14 18:05 ` [PATCH RFC 2/5] KVM: x86: introduce KVM_MEM_ALLONES memory Vitaly Kuznetsov
2020-05-14 19:18 ` Sean Christopherson
2020-05-15 8:24 ` Vitaly Kuznetsov
2020-05-14 18:05 ` [PATCH RFC 3/5] KVM: x86: move kvm_vcpu_gfn_to_memslot() out of try_async_pf() Vitaly Kuznetsov
2020-05-14 18:05 ` Vitaly Kuznetsov [this message]
2020-05-14 19:46 ` [PATCH RFC 4/5] KVM: x86: aggressively map PTEs in KVM_MEM_ALLONES slots Sean Christopherson
2020-05-15 8:36 ` Vitaly Kuznetsov
2020-05-15 13:58 ` Sean Christopherson
2020-05-14 18:05 ` [PATCH RFC 5/5] KVM: selftests: add KVM_MEM_ALLONES test Vitaly Kuznetsov
2020-05-14 22:05 ` [PATCH RFC 0/5] KVM: x86: KVM_MEM_ALLONES memory Peter Xu
2020-05-14 22:56 ` Sean Christopherson
2020-05-14 23:22 ` Peter Xu
2020-05-14 23:32 ` Sean Christopherson
2020-05-15 8:42 ` Vitaly Kuznetsov
2020-05-15 1:03 ` Andy Lutomirski
2020-05-15 11:15 ` Peter Xu
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