linux-kernel - [PATCH v2 5/9] KVM: x86/mmu: Factor out the meat of reset_tdp_shadow_zero_bits

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Date:   Mon, 21 Mar 2022 15:43:54 -0700
From:   Ben Gardon <bgardon@...gle.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>, Peter Xu <peterx@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        David Matlack <dmatlack@...gle.com>,
        Jim Mattson <jmattson@...gle.com>,
        David Dunn <daviddunn@...gle.com>,
        Jing Zhang <jingzhangos@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Ben Gardon <bgardon@...gle.com>
Subject: [PATCH v2 5/9] KVM: x86/mmu: Factor out the meat of reset_tdp_shadow_zero_bits_mask

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@...gle.com>
---
 arch/x86/kvm/mmu/mmu.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 3b8da8b0745e..6f98111f8f8b 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4487,16 +4487,14 @@ 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_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
@@ -4507,12 +4505,19 @@ reset_tdp_shadow_zero_bits_mask(struct kvm_mmu *context)
 	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_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.
-- 
2.35.1.894.gb6a874cedc-goog