From: Sean Christopherson <sean.j.christopherson@intel.com>
To: Paolo Bonzini <pbonzini@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,
eric van tassell <Eric.VanTassell@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>
Subject: [RFC PATCH 1/8] KVM: x86/mmu: Return old SPTE from mmu_spte_clear_track_bits()
Date: Fri, 31 Jul 2020 14:23:16 -0700 [thread overview]
Message-ID: <20200731212323.21746-2-sean.j.christopherson@intel.com> (raw)
In-Reply-To: <20200731212323.21746-1-sean.j.christopherson@intel.com>
Return the old SPTE when clearing a SPTE and push the "old SPTE present"
check to the caller. Tracking pinned SPTEs will use the old SPTE
in rmap_remove() to determine whether or not the SPTE is pinned.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
---
arch/x86/kvm/mmu/mmu.c | 12 +++++++-----
1 file changed, 7 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 289dddff2615f..d737042fea55e 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -930,9 +930,9 @@ static bool mmu_spte_update(u64 *sptep, u64 new_spte)
* Rules for using mmu_spte_clear_track_bits:
* It sets the sptep from present to nonpresent, and track the
* state bits, it is used to clear the last level sptep.
- * Returns non-zero if the PTE was previously valid.
+ * Returns the old PTE.
*/
-static int mmu_spte_clear_track_bits(u64 *sptep)
+static u64 mmu_spte_clear_track_bits(u64 *sptep)
{
kvm_pfn_t pfn;
u64 old_spte = *sptep;
@@ -943,7 +943,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
old_spte = __update_clear_spte_slow(sptep, 0ull);
if (!is_shadow_present_pte(old_spte))
- return 0;
+ return old_spte;
pfn = spte_to_pfn(old_spte);
@@ -960,7 +960,7 @@ static int mmu_spte_clear_track_bits(u64 *sptep)
if (is_dirty_spte(old_spte))
kvm_set_pfn_dirty(pfn);
- return 1;
+ return old_spte;
}
/*
@@ -1484,7 +1484,9 @@ static u64 *rmap_get_next(struct rmap_iterator *iter)
static void drop_spte(struct kvm *kvm, u64 *sptep)
{
- if (mmu_spte_clear_track_bits(sptep))
+ u64 old_spte = mmu_spte_clear_track_bits(sptep);
+
+ if (is_shadow_present_pte(old_spte))
rmap_remove(kvm, sptep);
}
--
2.28.0
next prev parent reply other threads:[~2020-07-31 21:24 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 21:23 [RFC PATCH 0/8] KVM: x86/mmu: Introduce pinned SPTEs framework Sean Christopherson
2020-07-31 21:23 ` Sean Christopherson [this message]
2020-07-31 21:23 ` [RFC PATCH 2/8] KVM: x86/mmu: Use bits 2:0 to check for present SPTEs Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 3/8] KVM: x86/mmu: Refactor handling of not-present SPTEs in mmu_set_spte() Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 4/8] KVM: x86/mmu: Add infrastructure for pinning PFNs on demand Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 5/8] KVM: SVM: Use the KVM MMU SPTE pinning hooks to pin pages " Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 6/8] KVM: x86/mmu: Move 'pfn' variable to caller of direct_page_fault() Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 7/8] KVM: x86/mmu: Introduce kvm_mmu_map_tdp_page() for use by SEV Sean Christopherson
2020-07-31 21:23 ` [RFC PATCH 8/8] KVM: SVM: Pin SEV pages in MMU during sev_launch_update_data() Sean Christopherson
2020-08-03 3:00 ` [RFC PATCH 0/8] KVM: x86/mmu: Introduce pinned SPTEs framework Eric van Tassell
2020-08-03 15:00 ` Sean Christopherson
2020-08-03 15:52 ` Brijesh Singh
2020-08-03 17:16 ` Sean Christopherson
2020-08-04 19:40 ` Brijesh Singh
2020-10-27 3:22 ` Brijesh Singh
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