sync_page() calls set_spte() from a loop across a page table. It would
work better if set_spte() left the TLB flushing to its callers, so that
sync_page() can aggregate into a single call.
Signed-off-by: Junaid Shahid <junaids@xxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 16 ++++++++++++----
arch/x86/kvm/paging_tmpl.h | 12 ++++++++----
2 files changed, 20 insertions(+), 8 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 8494dbae41b9..07f517fd6e95 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -2725,6 +2725,10 @@ static bool kvm_is_mmio_pfn(kvm_pfn_t pfn)
return true;
}
+/* Bits which may be returned by set_spte() */
+#define WRPROT_SHADOW_PT BIT(0)
+#define NEED_FLUSH_REMOTE_TLBS BIT(1)
+
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned pte_access, int level,
gfn_t gfn, kvm_pfn_t pfn, bool speculative,
@@ -2801,7 +2805,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if (mmu_need_write_protect(vcpu, gfn, can_unsync)) {
pgprintk("%s: found shadow page for %llx, marking ro\n",
__func__, gfn);
- ret = 1;
+ ret |= WRPROT_SHADOW_PT;
pte_access &= ~ACC_WRITE_MASK;
spte &= ~(PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE);
}
@@ -2817,7 +2821,7 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
set_pte:
if (mmu_spte_update(sptep, spte))
- kvm_flush_remote_tlbs(vcpu->kvm);
+ ret |= NEED_FLUSH_REMOTE_TLBS;
done:
return ret;
}
@@ -2828,6 +2832,7 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
{
int was_rmapped = 0;
int rmap_count;
+ int set_spte_ret;
int ret = RET_PF_RETRY;
pgprintk("%s: spte %llx write_fault %d gfn %llx\n", __func__,
@@ -2855,12 +2860,15 @@ static int mmu_set_spte(struct kvm_vcpu *vcpu, u64 *sptep, unsigned pte_access,
was_rmapped = 1;
}
- if (set_spte(vcpu, sptep, pte_access, level, gfn, pfn, speculative,
- true, host_writable)) {
+ set_spte_ret = set_spte(vcpu, sptep, pte_access, level, gfn, pfn,
+ speculative, true, host_writable);
+ if (set_spte_ret & WRPROT_SHADOW_PT) {
if (write_fault)
ret = RET_PF_EMULATE;
kvm_make_request(KVM_REQ_TLB_FLUSH, vcpu);
}
+ if (set_spte_ret & NEED_FLUSH_REMOTE_TLBS)
+ kvm_flush_remote_tlbs(vcpu->kvm);
if (unlikely(is_mmio_spte(*sptep)))
ret = RET_PF_EMULATE;
diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index 6288e9d7068e..f176b85767ec 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -968,6 +968,7 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
int i, nr_present = 0;
bool host_writable;
gpa_t first_pte_gpa;
+ int set_spte_ret = 0;
/* direct kvm_mmu_page can not be unsync. */
BUG_ON(sp->role.direct);
@@ -1024,12 +1025,15 @@ static int FNAME(sync_page)(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp)
host_writable = sp->spt[i] & SPTE_HOST_WRITEABLE;
- set_spte(vcpu, &sp->spt[i], pte_access,
- PT_PAGE_TABLE_LEVEL, gfn,
- spte_to_pfn(sp->spt[i]), true, false,
- host_writable);
+ set_spte_ret |= set_spte(vcpu, &sp->spt[i],
+ pte_access, PT_PAGE_TABLE_LEVEL,
+ gfn, spte_to_pfn(sp->spt[i]),
+ true, false, host_writable);
}
+ if (set_spte_ret & NEED_FLUSH_REMOTE_TLBS)
+ kvm_flush_remote_tlbs(vcpu->kvm);
+
return nr_present;
}
--
2.17.0.441.gb46fe60e1d-goog
