From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
David Matlack <dmatlack@google.com>,
Mingwei Zhang <mizhang@google.com>,
Yan Zhao <yan.y.zhao@intel.com>, Ben Gardon <bgardon@google.com>
Subject: [PATCH v4 8/9] KVM: x86/mmu: Add helper to convert SPTE value to its shadow page
Date: Tue, 30 Aug 2022 23:55:36 +0000 [thread overview]
Message-ID: <20220830235537.4004585-9-seanjc@google.com> (raw)
In-Reply-To: <20220830235537.4004585-1-seanjc@google.com>
Add a helper to convert a SPTE to its shadow page to deduplicate a
variety of flows and hopefully avoid future bugs, e.g. if KVM attempts to
get the shadow page for a SPTE without dropping high bits.
Opportunistically add a comment in mmu_free_root_page() documenting why
it treats the root HPA as a SPTE.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/kvm/mmu/mmu.c | 17 ++++++++++-------
arch/x86/kvm/mmu/mmu_internal.h | 12 ------------
arch/x86/kvm/mmu/spte.h | 17 +++++++++++++++++
arch/x86/kvm/mmu/tdp_mmu.h | 2 ++
4 files changed, 29 insertions(+), 19 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index de06c1f87635..4737da767a40 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -1808,7 +1808,7 @@ static int __mmu_unsync_walk(struct kvm_mmu_page *sp,
continue;
}
- child = to_shadow_page(ent & SPTE_BASE_ADDR_MASK);
+ child = spte_to_child_sp(ent);
if (child->unsync_children) {
if (mmu_pages_add(pvec, child, i))
@@ -2367,7 +2367,7 @@ static void validate_direct_spte(struct kvm_vcpu *vcpu, u64 *sptep,
* so we should update the spte at this point to get
* a new sp with the correct access.
*/
- child = to_shadow_page(*sptep & SPTE_BASE_ADDR_MASK);
+ child = spte_to_child_sp(*sptep);
if (child->role.access == direct_access)
return;
@@ -2388,7 +2388,7 @@ static int mmu_page_zap_pte(struct kvm *kvm, struct kvm_mmu_page *sp,
if (is_last_spte(pte, sp->role.level)) {
drop_spte(kvm, spte);
} else {
- child = to_shadow_page(pte & SPTE_BASE_ADDR_MASK);
+ child = spte_to_child_sp(pte);
drop_parent_pte(child, spte);
/*
@@ -2827,7 +2827,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
struct kvm_mmu_page *child;
u64 pte = *sptep;
- child = to_shadow_page(pte & SPTE_BASE_ADDR_MASK);
+ child = spte_to_child_sp(pte);
drop_parent_pte(child, sptep);
flush = true;
} else if (pfn != spte_to_pfn(*sptep)) {
@@ -3439,7 +3439,11 @@ static void mmu_free_root_page(struct kvm *kvm, hpa_t *root_hpa,
if (!VALID_PAGE(*root_hpa))
return;
- sp = to_shadow_page(*root_hpa & SPTE_BASE_ADDR_MASK);
+ /*
+ * The "root" may be a special root, e.g. a PAE entry, treat it as a
+ * SPTE to ensure any non-PA bits are dropped.
+ */
+ sp = spte_to_child_sp(*root_hpa);
if (WARN_ON(!sp))
return;
@@ -3924,8 +3928,7 @@ void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu)
hpa_t root = vcpu->arch.mmu->pae_root[i];
if (IS_VALID_PAE_ROOT(root)) {
- root &= SPTE_BASE_ADDR_MASK;
- sp = to_shadow_page(root);
+ sp = spte_to_child_sp(root);
mmu_sync_children(vcpu, sp, true);
}
}
diff --git a/arch/x86/kvm/mmu/mmu_internal.h b/arch/x86/kvm/mmu/mmu_internal.h
index 22152241bd29..dbaf6755c5a7 100644
--- a/arch/x86/kvm/mmu/mmu_internal.h
+++ b/arch/x86/kvm/mmu/mmu_internal.h
@@ -133,18 +133,6 @@ struct kvm_mmu_page {
extern struct kmem_cache *mmu_page_header_cache;
-static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
-{
- struct page *page = pfn_to_page(shadow_page >> PAGE_SHIFT);
-
- return (struct kvm_mmu_page *)page_private(page);
-}
-
-static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
-{
- return to_shadow_page(__pa(sptep));
-}
-
static inline int kvm_mmu_role_as_id(union kvm_mmu_page_role role)
{
return role.smm ? 1 : 0;
diff --git a/arch/x86/kvm/mmu/spte.h b/arch/x86/kvm/mmu/spte.h
index 7670c13ce251..7e5343339b90 100644
--- a/arch/x86/kvm/mmu/spte.h
+++ b/arch/x86/kvm/mmu/spte.h
@@ -219,6 +219,23 @@ static inline int spte_index(u64 *sptep)
*/
extern u64 __read_mostly shadow_nonpresent_or_rsvd_lower_gfn_mask;
+static inline struct kvm_mmu_page *to_shadow_page(hpa_t shadow_page)
+{
+ struct page *page = pfn_to_page((shadow_page) >> PAGE_SHIFT);
+
+ return (struct kvm_mmu_page *)page_private(page);
+}
+
+static inline struct kvm_mmu_page *spte_to_child_sp(u64 spte)
+{
+ return to_shadow_page(spte & SPTE_BASE_ADDR_MASK);
+}
+
+static inline struct kvm_mmu_page *sptep_to_sp(u64 *sptep)
+{
+ return to_shadow_page(__pa(sptep));
+}
+
static inline bool is_mmio_spte(u64 spte)
{
return (spte & shadow_mmio_mask) == shadow_mmio_value &&
diff --git a/arch/x86/kvm/mmu/tdp_mmu.h b/arch/x86/kvm/mmu/tdp_mmu.h
index c163f7cc23ca..d3714200b932 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.h
+++ b/arch/x86/kvm/mmu/tdp_mmu.h
@@ -5,6 +5,8 @@
#include <linux/kvm_host.h>
+#include "spte.h"
+
hpa_t kvm_tdp_mmu_get_vcpu_root_hpa(struct kvm_vcpu *vcpu);
__must_check static inline bool kvm_tdp_mmu_get_root(struct kvm_mmu_page *root)
--
2.37.2.672.g94769d06f0-goog
next prev parent reply other threads:[~2022-08-30 23:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-30 23:55 [PATCH v4 0/9] KVM: x86: Apply NX mitigation more precisely Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 1/9] KVM: x86/mmu: Bug the VM if KVM attempts to double count an NX huge page Sean Christopherson
2022-09-21 13:17 ` Vitaly Kuznetsov
2022-09-21 14:43 ` Sean Christopherson
2022-09-21 15:41 ` Sean Christopherson
2022-09-21 16:08 ` Vitaly Kuznetsov
2022-09-30 4:33 ` Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 2/9] KVM: x86/mmu: Tag disallowed NX huge pages even if they're not tracked Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 3/9] KVM: x86/mmu: Rename NX huge pages fields/functions for consistency Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 4/9] KVM: x86/mmu: Properly account NX huge page workaround for nonpaging MMUs Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 5/9] KVM: x86/mmu: Document implicit barriers/ordering in TDP MMU shared mode Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 6/9] KVM: x86/mmu: Set disallowed_nx_huge_page in TDP MMU before setting SPTE Sean Christopherson
2022-08-30 23:55 ` [PATCH v4 7/9] KVM: x86/mmu: Track the number of TDP MMU pages, but not the actual pages Sean Christopherson
2022-08-30 23:55 ` Sean Christopherson [this message]
2022-08-30 23:55 ` [PATCH v4 9/9] KVM: x86/mmu: explicitly check nx_hugepage in disallowed_hugepage_adjust() Sean Christopherson
2022-09-06 18:38 ` [PATCH v4 0/9] KVM: x86: Apply NX mitigation more precisely Mingwei Zhang
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220830235537.4004585-9-seanjc@google.com \
--to=seanjc@google.com \
--cc=bgardon@google.com \
--cc=dmatlack@google.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=mizhang@google.com \
--cc=pbonzini@redhat.com \
--cc=yan.y.zhao@intel.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.