diff mbox series

[09/15] KVM: x86/mmu: Factor out the meat of reset_tdp_shadow_zero_bits_mask

Message ID 20211115234603.2908381-10-bgardon@google.com (mailing list archive)
State New, archived
Headers show
Series Currently disabling dirty logging with the TDP MMU is extremely slow. On a 96 vCPU / 96G VM it takes ~45 seconds to disable dirty logging with the TDP MMU, as opposed to ~3.5 seconds with the legacy MMU. This series optimizes TLB flushes and intro | expand

Commit Message

Ben Gardon Nov. 15, 2021, 11:45 p.m. UTC 
Factor out the implementation of reset_tdp_shadow_zero_bits_mask to a
helper function which does not require a vCPU pointer. The only element
of the struct kvm_mmu context used by the function is the shadow root
level, so pass that in too instead of the mmu context.

No functional change intended.


Signed-off-by: Ben Gardon <bgardon@google.com>
---
 arch/x86/kvm/mmu/mmu.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)
diff mbox series

Patch

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 1e890509b93f..fdf0f15ab19d 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4450,17 +4450,14 @@  static inline bool boot_cpu_is_amd(void)
  * possible, however, kvm currently does not do execution-protection.
  */
 static void
-reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
-				struct kvm_mmu *context)
+build_tdp_shadow_zero_bits_mask(struct rsvd_bits_validate *shadow_zero_check,
+				int shadow_root_level)
 {
-	struct rsvd_bits_validate *shadow_zero_check;
 	int i;
 
-	shadow_zero_check = &context->shadow_zero_check;
-
 	if (boot_cpu_is_amd())
 		__reset_rsvds_bits_mask(shadow_zero_check, reserved_hpa_bits(),
-					context->shadow_root_level, false,
+					shadow_root_level, false,
 					boot_cpu_has(X86_FEATURE_GBPAGES),
 					false, true);
 	else
@@ -4470,12 +4467,20 @@  reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
 	if (!shadow_me_mask)
 		return;
 
-	for (i = context->shadow_root_level; --i >= 0;) {
+	for (i = shadow_root_level; --i >= 0;) {
 		shadow_zero_check->rsvd_bits_mask[0][i] &= ~shadow_me_mask;
 		shadow_zero_check->rsvd_bits_mask[1][i] &= ~shadow_me_mask;
 	}
 }
 
+static void
+reset_tdp_shadow_zero_bits_mask(struct kvm_vcpu *vcpu,
+				struct kvm_mmu *context)
+{
+	build_tdp_shadow_zero_bits_mask(&context->shadow_zero_check,
+					context->shadow_root_level);
+}
+
 /*
  * as the comments in reset_shadow_zero_bits_mask() except it
  * is the shadow page table for intel nested guest.