[Xen-devel] [PATCH v19 12/14] x86/VPMU: Merge vpmu_rdmsr and vpmu_wrmsr

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

The two routines share most of their logic.

Signed-off-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
---
Changes in v19:
* const-ified arch_vpmu_ops in vpmu_do_wrmsr
* non-changes:
   - kept 'current' as a non-initializer to avoid unnecessary initialization
     in the (common) non-VPMU case
   - kept 'nop' label since there are multiple dissimilar cases that can cause
     a non-emulation of VPMU access

 xen/arch/x86/hvm/vpmu.c        | 76 +++++++++++++++++-------------------------
 xen/include/asm-x86/hvm/vpmu.h | 14 ++++++--
 2 files changed, 42 insertions(+), 48 deletions(-)

diff --git a/xen/arch/x86/hvm/vpmu.c b/xen/arch/x86/hvm/vpmu.c
index c287d8b..beed956 100644
--- a/xen/arch/x86/hvm/vpmu.c
+++ b/xen/arch/x86/hvm/vpmu.c
@@ -103,63 +103,47 @@ void vpmu_lvtpc_update(uint32_t val)
         apic_write(APIC_LVTPC, vpmu->hw_lapic_lvtpc);
 }
 
-int vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content, uint64_t supported)
+int vpmu_do_msr(unsigned int msr, uint64_t *msr_content,
+                uint64_t supported, bool_t is_write)
 {
-    struct vcpu *curr = current;
+    struct vcpu *curr;
     struct vpmu_struct *vpmu;
+    const struct arch_vpmu_ops *ops;
+    int ret = 0;
 
     if ( vpmu_mode == XENPMU_MODE_OFF )
-        return 0;
+        goto nop;
 
+    curr = current;
     vpmu = vcpu_vpmu(curr);
-    if ( vpmu->arch_vpmu_ops && vpmu->arch_vpmu_ops->do_wrmsr )
-    {
-        int ret = vpmu->arch_vpmu_ops->do_wrmsr(msr, msr_content, supported);
-
-        /*
-         * We may have received a PMU interrupt during WRMSR handling
-         * and since do_wrmsr may load VPMU context we should save
-         * (and unload) it again.
-         */
-        if ( !is_hvm_vcpu(curr) && vpmu->xenpmu_data &&
-             (vpmu->xenpmu_data->pmu.pmu_flags & PMU_CACHED) )
-        {
-            vpmu_set(vpmu, VPMU_CONTEXT_SAVE);
-            vpmu->arch_vpmu_ops->arch_vpmu_save(curr);
-            vpmu_reset(vpmu, VPMU_CONTEXT_SAVE | VPMU_CONTEXT_LOADED);
-        }
-        return ret;
-    }
-
-    return 0;
-}
-
-int vpmu_do_rdmsr(unsigned int msr, uint64_t *msr_content)
-{
-    struct vcpu *curr = current;
-    struct vpmu_struct *vpmu;
+    ops = vpmu->arch_vpmu_ops;
+    if ( !ops )
+        goto nop;
+
+    if ( is_write && ops->do_wrmsr )
+        ret = ops->do_wrmsr(msr, *msr_content, supported);
+    else if ( !is_write && ops->do_rdmsr )
+        ret = ops->do_rdmsr(msr, msr_content);
+    else
+        goto nop;
 
-    if ( vpmu_mode == XENPMU_MODE_OFF )
+    /*
+     * We may have received a PMU interrupt while handling MSR access
+     * and since do_wr/rdmsr may load VPMU context we should save
+     * (and unload) it again.
+     */
+    if ( !is_hvm_vcpu(curr) &&
+         vpmu->xenpmu_data && (vpmu->xenpmu_data->pmu.pmu_flags & PMU_CACHED) )
     {
-        *msr_content = 0;
-        return 0;
+        vpmu_set(vpmu, VPMU_CONTEXT_SAVE);
+        ops->arch_vpmu_save(curr);
+        vpmu_reset(vpmu, VPMU_CONTEXT_SAVE | VPMU_CONTEXT_LOADED);
     }
 
-    vpmu = vcpu_vpmu(curr);
-    if ( vpmu->arch_vpmu_ops && vpmu->arch_vpmu_ops->do_rdmsr )
-    {
-        int ret = vpmu->arch_vpmu_ops->do_rdmsr(msr, msr_content);
+    return ret;
 
-        if ( !is_hvm_vcpu(curr) && vpmu->xenpmu_data &&
-             (vpmu->xenpmu_data->pmu.pmu_flags & PMU_CACHED) )
-        {
-            vpmu_set(vpmu, VPMU_CONTEXT_SAVE);
-            vpmu->arch_vpmu_ops->arch_vpmu_save(curr);
-            vpmu_reset(vpmu, VPMU_CONTEXT_SAVE | VPMU_CONTEXT_LOADED);
-        }
-        return ret;
-    }
-    else
+ nop:
+    if ( !is_write )
         *msr_content = 0;
 
     return 0;
diff --git a/xen/include/asm-x86/hvm/vpmu.h b/xen/include/asm-x86/hvm/vpmu.h
index 642a4b7..63851a7 100644
--- a/xen/include/asm-x86/hvm/vpmu.h
+++ b/xen/include/asm-x86/hvm/vpmu.h
@@ -99,8 +99,8 @@ static inline bool_t vpmu_are_all_set(const struct 
vpmu_struct *vpmu,
 }
 
 void vpmu_lvtpc_update(uint32_t val);
-int vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content, uint64_t supported);
-int vpmu_do_rdmsr(unsigned int msr, uint64_t *msr_content);
+int vpmu_do_msr(unsigned int msr, uint64_t *msr_content,
+                uint64_t supported, bool_t is_write);
 void vpmu_do_interrupt(struct cpu_user_regs *regs);
 void vpmu_do_cpuid(unsigned int input, unsigned int *eax, unsigned int *ebx,
                                        unsigned int *ecx, unsigned int *edx);
@@ -110,6 +110,16 @@ void vpmu_save(struct vcpu *v);
 void vpmu_load(struct vcpu *v);
 void vpmu_dump(struct vcpu *v);
 
+static inline int vpmu_do_wrmsr(unsigned int msr, uint64_t msr_content,
+                                uint64_t supported)
+{
+    return vpmu_do_msr(msr, &msr_content, supported, 1);
+}
+static inline int vpmu_do_rdmsr(unsigned int msr, uint64_t *msr_content)
+{
+    return vpmu_do_msr(msr, msr_content, 0, 0);
+}
+
 extern int acquire_pmu_ownership(int pmu_ownership);
 extern void release_pmu_ownership(int pmu_ownership);
 
-- 
1.8.1.4


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