[PATCH] KVM: x86/mmu: Remove unused "const u8 *new" for kvm_mmu_track_write()

[PATCH] KVM: x86/mmu: Remove unused "const u8 *new" for kvm_mmu_track_write()

[Like Xu]

From: Like Xu <likexu@tencent.com>

The incoming parameter @new has not been required since commit 0e0fee5c539b
("kvm: mmu: Fix race in emulated page table writes"). And the callback
kvmgt_page_track_write() registered by KVMGT still formally consumes it.

No functional change intended.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
---
 arch/x86/kvm/mmu.h            | 3 +--
 arch/x86/kvm/mmu/mmu.c        | 3 +--
 arch/x86/kvm/mmu/page_track.h | 2 +-
 3 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/mmu.h b/arch/x86/kvm/mmu.h
index 253fb2093d5d..27531ce6b739 100644
--- a/arch/x86/kvm/mmu.h
+++ b/arch/x86/kvm/mmu.h
@@ -121,8 +121,7 @@ void kvm_mmu_unload(struct kvm_vcpu *vcpu);
 void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu);
 void kvm_mmu_sync_roots(struct kvm_vcpu *vcpu);
 void kvm_mmu_sync_prev_roots(struct kvm_vcpu *vcpu);
-void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
-			 int bytes);
+void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes);
 
 static inline int kvm_mmu_reload(struct kvm_vcpu *vcpu)
 {
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 9e4cd8b4a202..d742fae074c1 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5638,8 +5638,7 @@ static u64 *get_written_sptes(struct kvm_mmu_page *sp, gpa_t gpa, int *nspte)
 	return spte;
 }
 
-void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
-			 int bytes)
+void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
 {
 	gfn_t gfn = gpa >> PAGE_SHIFT;
 	struct kvm_mmu_page *sp;
diff --git a/arch/x86/kvm/mmu/page_track.h b/arch/x86/kvm/mmu/page_track.h
index 62f98c6c5af3..ea5dfd53b5c4 100644
--- a/arch/x86/kvm/mmu/page_track.h
+++ b/arch/x86/kvm/mmu/page_track.h
@@ -52,7 +52,7 @@ static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 {
 	__kvm_page_track_write(vcpu->kvm, gpa, new, bytes);
 
-	kvm_mmu_track_write(vcpu, gpa, new, bytes);
+	kvm_mmu_track_write(vcpu, gpa, bytes);
 }
 
 #endif /* __KVM_X86_PAGE_TRACK_H */

base-commit: 240f736891887939571854bd6d734b6c9291f22e
-- 
2.41.0

Re: [PATCH] KVM: x86/mmu: Remove unused "const u8 *new" for kvm_mmu_track_write()

[Sean Christopherson]

On Tue, Aug 08, 2023, Like Xu wrote:
> From: Like Xu <likexu@tencent.com>
> 
> The incoming parameter @new has not been required since commit 0e0fee5c539b
> ("kvm: mmu: Fix race in emulated page table writes"). And the callback
> kvmgt_page_track_write() registered by KVMGT still formally consumes it.
> 
> No functional change intended.
> 
> Suggested-by: Sean Christopherson <seanjc@google.com>

No need to give me credit, you spotted the unnecessary param, all I did was confirm
that it wasn't needed.

> -void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, const u8 *new,
> -			 int bytes)
> +void kvm_mmu_track_write(struct kvm_vcpu *vcpu, gpa_t gpa, int bytes)
>  {
>  	gfn_t gfn = gpa >> PAGE_SHIFT;
>  	struct kvm_mmu_page *sp;
> diff --git a/arch/x86/kvm/mmu/page_track.h b/arch/x86/kvm/mmu/page_track.h
> index 62f98c6c5af3..ea5dfd53b5c4 100644
> --- a/arch/x86/kvm/mmu/page_track.h
> +++ b/arch/x86/kvm/mmu/page_track.h
> @@ -52,7 +52,7 @@ static inline void kvm_page_track_write(struct kvm_vcpu *vcpu, gpa_t gpa,

Please remove it from the entire kvm_page_track_write() chain.  Yes, it will be
a larger patch and need an ack from the KVMGT folks, but there is no reason to
only do a partial cleanup