[Xen-devel] [PATCH v2] hvm/vpmu: Prevent dump handlers from incorrectly mutating state

["Jan Beulich" <JBeulich@xxxxxxxx>]

Discovered by Coverity, CID 1055181

core2_vpmu_dump() was incorrectly setting VPMU_CONTEXT_LOADED when it
was intending to check for it.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

This would have been avoided if the dump function declared all its
pointers "const" - doing this now (also in SVM).

Also fixing some indentation issues at once.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/arch/x86/hvm/svm/vpmu.c
+++ b/xen/arch/x86/hvm/svm/vpmu.c
@@ -415,10 +415,10 @@ static void amd_vpmu_destroy(struct vcpu
 }
 
 /* VPMU part of the 'q' keyhandler */
-static void amd_vpmu_dump(struct vcpu *v)
+static void amd_vpmu_dump(const struct vcpu *v)
 {
-    struct vpmu_struct *vpmu = vcpu_vpmu(v);
-    struct amd_vpmu_context *ctxt = vpmu->context;
+    const struct vpmu_struct *vpmu = vcpu_vpmu(v);
+    const struct amd_vpmu_context *ctxt = vpmu->context;
     unsigned int i;
 
     printk("    VPMU state: 0x%x ", vpmu->flags);
@@ -447,9 +447,9 @@ static void amd_vpmu_dump(struct vcpu *v
 
         rdmsrl(ctrls[i], ctrl);
         rdmsrl(counters[i], cntr);
-        printk("      0x%08x: 0x%lx (0x%lx in HW)    0x%08x: 0x%lx (0x%lx in 
HW)\n",
-            ctrls[i], ctxt->ctrls[i], ctrl,
-            counters[i], ctxt->counters[i], cntr);
+        printk("      %#x: %#lx (%#lx in HW)    %#x: %#lx (%#lx in HW)\n",
+               ctrls[i], ctxt->ctrls[i], ctrl,
+               counters[i], ctxt->counters[i], cntr);
     }
 }
 
--- a/xen/arch/x86/hvm/vmx/vpmu_core2.c
+++ b/xen/arch/x86/hvm/vmx/vpmu_core2.c
@@ -678,11 +678,11 @@ static void core2_vpmu_do_cpuid(unsigned
 }
 
 /* Dump vpmu info on console, called in the context of keyhandler 'q'. */
-static void core2_vpmu_dump(struct vcpu *v)
+static void core2_vpmu_dump(const struct vcpu *v)
 {
-    struct vpmu_struct *vpmu = vcpu_vpmu(v);
+    const struct vpmu_struct *vpmu = vcpu_vpmu(v);
     int i, num;
-    struct core2_vpmu_context *core2_vpmu_cxt = NULL;
+    const struct core2_vpmu_context *core2_vpmu_cxt = NULL;
     u64 val;
 
     if ( !vpmu_is_set(vpmu, VPMU_CONTEXT_ALLOCATED) )
@@ -690,7 +690,7 @@ static void core2_vpmu_dump(struct vcpu 
 
     if ( !vpmu_is_set(vpmu, VPMU_RUNNING) )
     {
-        if ( vpmu_set(vpmu, VPMU_CONTEXT_LOADED) )
+        if ( vpmu_is_set(vpmu, VPMU_CONTEXT_LOADED) )
             printk("    vPMU loaded\n");
         else
             printk("    vPMU allocated\n");
@@ -703,10 +703,11 @@ static void core2_vpmu_dump(struct vcpu 
     /* Print the contents of the counter and its configuration msr. */
     for ( i = 0; i < num; i++ )
     {
-        struct arch_msr_pair* msr_pair = core2_vpmu_cxt->arch_msr_pair;
+        const struct arch_msr_pair *msr_pair = core2_vpmu_cxt->arch_msr_pair;
+
         if ( core2_vpmu_cxt->pmu_enable->arch_pmc_enable[i] )
             printk("      general_%d: 0x%016lx ctrl: 0x%016lx\n",
-                             i, msr_pair[i].counter, msr_pair[i].control);
+                   i, msr_pair[i].counter, msr_pair[i].control);
     }
     /*
      * The configuration of the fixed counter is 4 bits each in the
@@ -716,9 +717,9 @@ static void core2_vpmu_dump(struct vcpu 
     for ( i = 0; i < core2_fix_counters.num; i++ )
     {
         if ( core2_vpmu_cxt->pmu_enable->fixed_ctr_enable[i] )
-            printk("      fixed_%d:   0x%016lx ctrl: 0x%lx\n",
-                             i, core2_vpmu_cxt->fix_counters[i],
-                             val & FIXED_CTR_CTRL_MASK);
+            printk("      fixed_%d:   0x%016lx ctrl: %#lx\n",
+                   i, core2_vpmu_cxt->fix_counters[i],
+                   val & FIXED_CTR_CTRL_MASK);
         val >>= FIXED_CTR_CTRL_BITS;
     }
 }
--- a/xen/include/asm-x86/hvm/vpmu.h
+++ b/xen/include/asm-x86/hvm/vpmu.h
@@ -54,7 +54,7 @@ struct arch_vpmu_ops {
     void (*arch_vpmu_destroy)(struct vcpu *v);
     int (*arch_vpmu_save)(struct vcpu *v);
     void (*arch_vpmu_load)(struct vcpu *v);
-    void (*arch_vpmu_dump)(struct vcpu *v);
+    void (*arch_vpmu_dump)(const struct vcpu *);
 };
 
 int vmx_vpmu_initialise(struct vcpu *, unsigned int flags);

Attachment: x86-vPMU-dump-ro.patch
Description: Text document

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel