It makes set_spte more clean and reduces branch prediction
Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/mmu.c | 37 ++++++++++++++++++++++++++-----------
1 files changed, 26 insertions(+), 11 deletions(-)
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index 43b7e0c..a8a9c0e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -235,6 +235,29 @@ static inline u64 rsvd_bits(int s, int e)
return ((1ULL << (e - s + 1)) - 1) << s;
}
+static u64 gaccess_to_spte_access[ACC_ALL + 1];
+static void build_access_table(void)
+{
+ int access;
+
+ for (access = 0; access < ACC_ALL + 1; access++) {
+ u64 spte_access = 0;
+
+ if (access & ACC_EXEC_MASK)
+ spte_access |= shadow_x_mask;
+ else
+ spte_access |= shadow_nx_mask;
+
+ if (access & ACC_USER_MASK)
+ spte_access |= shadow_user_mask;
+
+ if (access & ACC_WRITE_MASK)
+ spte_access |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
+
+ gaccess_to_spte_access[access] = spte_access;
+ }
+}
+
void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
u64 dirty_mask, u64 nx_mask, u64 x_mask)
{
@@ -243,6 +266,7 @@ void kvm_mmu_set_mask_ptes(u64 user_mask, u64 accessed_mask,
shadow_dirty_mask = dirty_mask;
shadow_nx_mask = nx_mask;
shadow_x_mask = x_mask;
+ build_access_table();
}
EXPORT_SYMBOL_GPL(kvm_mmu_set_mask_ptes);
@@ -2391,20 +2415,11 @@ static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
if (!speculative)
spte |= shadow_accessed_mask;
- if (pte_access & ACC_EXEC_MASK)
- spte |= shadow_x_mask;
- else
- spte |= shadow_nx_mask;
-
- if (pte_access & ACC_USER_MASK)
- spte |= shadow_user_mask;
-
- if (pte_access & ACC_WRITE_MASK)
- spte |= PT_WRITABLE_MASK | SPTE_MMU_WRITEABLE;
-
if (level > PT_PAGE_TABLE_LEVEL)
spte |= PT_PAGE_SIZE_MASK;
+ spte |= gaccess_to_spte_access[pte_access];
+
if (tdp_enabled)
spte |= kvm_x86_ops->get_mt_mask(vcpu, gfn,
kvm_is_mmio_pfn(pfn));
--
1.7.7.6
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