x86/xen/msr: Remove pmu_msr_{read,write}()

As pmu_msr_{read,write}() are now wrappers of pmu_msr_chk_emulated(),
remove them and use pmu_msr_chk_emulated() directly.

As pmu_msr_chk_emulated() could easily return false in the cases where
it would set *emul to false, remove the "emul" argument and use the
return value instead.

While at it, convert the data type of MSR index to u32 in functions
called in pmu_msr_chk_emulated().

Suggested-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Xin Li (Intel) <xin@zytor.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20250427092027.1598740-12-xin@zytor.com

3 files changed, 17 insertions, 34 deletions

diff --git a/arch/x86/xen/enlighten_pv.c b/arch/x86/xen/enlighten_pv.c
index 530b59b0589c..719370d36622 100644
--- a/arch/x86/xen/enlighten_pv.c
+++ b/arch/x86/xen/enlighten_pv.c
@@ -1091,7 +1091,7 @@ static u64 xen_do_read_msr(unsigned int msr, int *err)
 {
 	u64 val = 0;	/* Avoid uninitialized value for safe variant. */
 
-	if (pmu_msr_read_emulated(msr, &val))
+	if (pmu_msr_chk_emulated(msr, &val, true))
 		return val;
 
 	if (err)
@@ -1163,12 +1163,13 @@ static void xen_do_write_msr(unsigned int msr, unsigned int low,
 	default:
 		val = (u64)high << 32 | low;
 
-		if (!pmu_msr_write_emulated(msr, val)) {
-			if (err)
-				*err = native_write_msr_safe(msr, low, high);
-			else
-				native_write_msr(msr, low, high);
-		}
+		if (pmu_msr_chk_emulated(msr, &val, false))
+			return;
+
+		if (err)
+			*err = native_write_msr_safe(msr, low, high);
+		else
+			native_write_msr(msr, low, high);
 	}
 }
 
diff --git a/arch/x86/xen/pmu.c b/arch/x86/xen/pmu.c
index 0062dbbd6661..043d72b060ed 100644
--- a/arch/x86/xen/pmu.c
+++ b/arch/x86/xen/pmu.c
@@ -129,7 +129,7 @@ static inline uint32_t get_fam15h_addr(u32 addr)
 	return addr;
 }
 
-static inline bool is_amd_pmu_msr(unsigned int msr)
+static bool is_amd_pmu_msr(u32 msr)
 {
 	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
@@ -195,8 +195,7 @@ static bool is_intel_pmu_msr(u32 msr_index, int *type, int *index)
 	}
 }
 
-static bool xen_intel_pmu_emulate(unsigned int msr, u64 *val, int type,
-				  int index, bool is_read)
+static bool xen_intel_pmu_emulate(u32 msr, u64 *val, int type, int index, bool is_read)
 {
 	uint64_t *reg = NULL;
 	struct xen_pmu_intel_ctxt *ctxt;
@@ -258,7 +257,7 @@ static bool xen_intel_pmu_emulate(unsigned int msr, u64 *val, int type,
 	return false;
 }
 
-static bool xen_amd_pmu_emulate(unsigned int msr, u64 *val, bool is_read)
+static bool xen_amd_pmu_emulate(u32 msr, u64 *val, bool is_read)
 {
 	uint64_t *reg = NULL;
 	int i, off = 0;
@@ -299,33 +298,17 @@ static bool xen_amd_pmu_emulate(unsigned int msr, u64 *val, bool is_read)
 	return false;
 }
 
-static bool pmu_msr_chk_emulated(unsigned int msr, uint64_t *val, bool is_read,
-				 bool *emul)
+bool pmu_msr_chk_emulated(u32 msr, u64 *val, bool is_read)
 {
 	int type, index = 0;
 
 	if (is_amd_pmu_msr(msr))
-		*emul = xen_amd_pmu_emulate(msr, val, is_read);
-	else if (is_intel_pmu_msr(msr, &type, &index))
-		*emul = xen_intel_pmu_emulate(msr, val, type, index, is_read);
-	else
-		return false;
-
-	return true;
-}
-
-bool pmu_msr_read_emulated(u32 msr, u64 *val)
-{
-	bool emulated;
+		return xen_amd_pmu_emulate(msr, val, is_read);
 
-	return pmu_msr_chk_emulated(msr, val, true, &emulated) && emulated;
-}
+	if (is_intel_pmu_msr(msr, &type, &index))
+		return xen_intel_pmu_emulate(msr, val, type, index, is_read);
 
-bool pmu_msr_write_emulated(u32 msr, u64 val)
-{
-	bool emulated;
-
-	return pmu_msr_chk_emulated(msr, &val, false, &emulated) && emulated;
+	return false;
 }
 
 static u64 xen_amd_read_pmc(int counter)
diff --git a/arch/x86/xen/xen-ops.h b/arch/x86/xen/xen-ops.h
index 2de30618aa5e..090349baec09 100644
--- a/arch/x86/xen/xen-ops.h
+++ b/arch/x86/xen/xen-ops.h
@@ -271,8 +271,7 @@ void xen_pmu_finish(int cpu);
 static inline void xen_pmu_init(int cpu) {}
 static inline void xen_pmu_finish(int cpu) {}
 #endif
-bool pmu_msr_read_emulated(u32 msr, u64 *val);
-bool pmu_msr_write_emulated(u32 msr, u64 val);
+bool pmu_msr_chk_emulated(u32 msr, u64 *val, bool is_read);
 int pmu_apic_update(uint32_t reg);
 u64 xen_read_pmc(int counter);