From 3a3f1e9dfa069fbed57a19b7de111ba50ead2d70 Mon Sep 17 00:00:00 2001
From: Peter Grehan <grehan@FreeBSD.org>
Date: Tue, 18 Aug 2020 11:36:38 +0000
Subject: [PATCH] Export a routine to provide the	TSC_AUX MSR value and
 use this in vmm.

Also, drop an unnecessary set of braces.

Requested by:	kib
Reviewed by:	kib
MFC after:	3 weeks
---
 sys/amd64/amd64/initcpu.c     | 11 ++++++++++-
 sys/amd64/vmm/intel/vmx_msr.c | 10 +++++-----
 sys/i386/i386/initcpu.c       | 11 ++++++++++-
 sys/x86/include/x86_var.h     |  1 +
 4 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/sys/amd64/amd64/initcpu.c b/sys/amd64/amd64/initcpu.c
index b584273aff6c..eab1d49f2b73 100644
--- a/sys/amd64/amd64/initcpu.c
+++ b/sys/amd64/amd64/initcpu.c
@@ -217,6 +217,15 @@ init_via(void)
 		wrmsr(0x1107, rdmsr(0x1107) | (1 << 28));
 }
 
+/*
+ * The value for the TSC_AUX MSR and rdtscp/rdpid.
+ */
+u_int
+cpu_auxmsr(void)
+{
+	return (PCPU_GET(cpuid));
+}
+
 /*
  * Initialize CPU control registers
  */
@@ -283,7 +292,7 @@ initializecpu(void)
 
 	if ((amd_feature & AMDID_RDTSCP) != 0 ||
 	    (cpu_stdext_feature2 & CPUID_STDEXT2_RDPID) != 0)
-		wrmsr(MSR_TSC_AUX, PCPU_GET(cpuid));
+		wrmsr(MSR_TSC_AUX, cpu_auxmsr());
 }
 
 void
diff --git a/sys/amd64/vmm/intel/vmx_msr.c b/sys/amd64/vmm/intel/vmx_msr.c
index 2d85681b4b9a..c8473fc0e603 100644
--- a/sys/amd64/vmm/intel/vmx_msr.c
+++ b/sys/amd64/vmm/intel/vmx_msr.c
@@ -365,9 +365,9 @@ void
 vmx_msr_guest_enter_tsc_aux(struct vmx *vmx, int vcpuid)
 {
 	uint64_t guest_tsc_aux = vmx->guest_msrs[vcpuid][IDX_MSR_TSC_AUX];
-	uint32_t cpuid = PCPU_GET(cpuid);
+	uint32_t host_aux = cpu_auxmsr();
 
-	if (vmx_have_msr_tsc_aux(vmx) && (guest_tsc_aux != cpuid))
+	if (vmx_have_msr_tsc_aux(vmx) && guest_tsc_aux != host_aux)
 		wrmsr(MSR_TSC_AUX, guest_tsc_aux);
 }
 
@@ -396,9 +396,9 @@ void
 vmx_msr_guest_exit_tsc_aux(struct vmx *vmx, int vcpuid)
 {
 	uint64_t guest_tsc_aux = vmx->guest_msrs[vcpuid][IDX_MSR_TSC_AUX];
-	uint32_t cpuid = PCPU_GET(cpuid);
+	uint32_t host_aux = cpu_auxmsr();
 
-	if (vmx_have_msr_tsc_aux(vmx) && (guest_tsc_aux != cpuid))
+	if (vmx_have_msr_tsc_aux(vmx) && guest_tsc_aux != host_aux)
 		/*
 		 * Note that it is not necessary to save the guest value
 		 * here; vmx->guest_msrs[vcpuid][IDX_MSR_TSC_AUX] always
@@ -406,7 +406,7 @@ vmx_msr_guest_exit_tsc_aux(struct vmx *vmx, int vcpuid)
 		 * the guest writes to it (which is expected to be very
 		 * rare).
 		 */
-		wrmsr(MSR_TSC_AUX, cpuid);
+		wrmsr(MSR_TSC_AUX, host_aux);
 }
 
 int
diff --git a/sys/i386/i386/initcpu.c b/sys/i386/i386/initcpu.c
index 93a0343ede32..ba86f30cf31c 100644
--- a/sys/i386/i386/initcpu.c
+++ b/sys/i386/i386/initcpu.c
@@ -627,6 +627,15 @@ init_transmeta(void)
 }
 #endif
 
+/*
+ * The value for the TSC_AUX MSR and rdtscp/rdpid.
+ */
+u_int
+cpu_auxmsr(void)
+{
+	return (PCPU_GET(cpuid));
+}
+
 extern int elf32_nxstack;
 
 void
@@ -751,7 +760,7 @@ initializecpu(void)
 	}
 	if ((amd_feature & AMDID_RDTSCP) != 0 ||
 	    (cpu_stdext_feature2 & CPUID_STDEXT2_RDPID) != 0)
-		wrmsr(MSR_TSC_AUX, PCPU_GET(cpuid));
+		wrmsr(MSR_TSC_AUX, cpu_auxmsr());
 }
 
 void
diff --git a/sys/x86/include/x86_var.h b/sys/x86/include/x86_var.h
index 3b908068bff3..789b8a2cbc48 100644
--- a/sys/x86/include/x86_var.h
+++ b/sys/x86/include/x86_var.h
@@ -115,6 +115,7 @@ typedef void alias_for_inthand_t(void);
 bool	acpi_get_fadt_bootflags(uint16_t *flagsp);
 void	*alloc_fpusave(int flags);
 void	busdma_swi(void);
+u_int	cpu_auxmsr(void);
 vm_paddr_t cpu_getmaxphyaddr(void);
 bool	cpu_mwait_usable(void);
 void	cpu_probe_amdc1e(void);