x86/time: Rework pv_soft_rdtsc() to aid further cleanup

Having pv_soft_rdtsc() emulate all parts of an rdtscp is awkward, and gets in
the way of some intended cleanup.

 * Drop the rdtscp parameter and always make the caller responsible for ecx
   updates when appropriate.
 * Switch the function from being void, and return the main timestamp in the
   return value.

The regs parameter is still needed, but only for the stats collection, once
again bringing into question their utility.  The parameter can however switch
to being const.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

diff --git a/xen/arch/x86/pv/emul-inv-op.c b/xen/arch/x86/pv/emul-inv-op.c
index f8944170d51d7a48b92826d5f4b10df97ae537f9..be95a5ff8d735e6ff333d8e94a1a0a63771f32a6 100644 (file)
--- a/xen/arch/x86/pv/emul-inv-op.c
+++ b/xen/arch/x86/pv/emul-inv-op.c
@@ -46,6 +46,7 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs *regs)
     char opcode[3];
     unsigned long eip, rc;
     struct vcpu *v = current;
+    const struct domain *currd = v->domain;
 
     eip = regs->rip;
     if ( (rc = copy_from_user(opcode, (char *)eip, sizeof(opcode))) != 0 )
@@ -56,7 +57,11 @@ static int emulate_invalid_rdtscp(struct cpu_user_regs *regs)
     if ( memcmp(opcode, "\xf\x1\xf9", sizeof(opcode)) )
         return 0;
     eip += sizeof(opcode);
-    pv_soft_rdtsc(v, regs, 1);
+
+    msr_split(regs, pv_soft_rdtsc(v, regs));
+    regs->rcx = (currd->arch.tsc_mode == TSC_MODE_PVRDTSCP
+                 ? currd->arch.incarnation : 0);
+
     pv_emul_instruction_done(regs, eip);
     return EXCRET_fault_fixed;
 }

diff --git a/xen/arch/x86/pv/emul-priv-op.c b/xen/arch/x86/pv/emul-priv-op.c
index 17aaf97f103aa8ae245a8355733ce943053a892b..a6bad88488b2d1050dfc65868795d6e4ed0b932d 100644 (file)
--- a/xen/arch/x86/pv/emul-priv-op.c
+++ b/xen/arch/x86/pv/emul-priv-op.c
@@ -1374,10 +1374,14 @@ int pv_emulate_privileged_op(struct cpu_user_regs *regs)
     case X86EMUL_OKAY:
         if ( ctxt.tsc & TSC_BASE )
         {
-            if ( ctxt.tsc & TSC_AUX )
-                pv_soft_rdtsc(curr, regs, 1);
-            else if ( currd->arch.vtsc )
-                pv_soft_rdtsc(curr, regs, 0);
+            if ( currd->arch.vtsc || (ctxt.tsc & TSC_AUX) )
+            {
+                msr_split(regs, pv_soft_rdtsc(curr, regs));
+
+                if ( ctxt.tsc & TSC_AUX )
+                    regs->rcx = (currd->arch.tsc_mode == TSC_MODE_PVRDTSCP
+                                 ? currd->arch.incarnation : 0);
+            }
             else
                 msr_split(regs, rdtsc());
         }

diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index c90524de9c266a5a7dd18a929b6731f60a4f3222..1a6fde65dd9a1c4848a946244d23a721158dfa74 100644 (file)
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -2024,7 +2024,7 @@ u64 gtsc_to_gtime(struct domain *d, u64 tsc)
     return time;
 }
 
-void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp)
+uint64_t pv_soft_rdtsc(const struct vcpu *v, const struct cpu_user_regs *regs)
 {
     s_time_t now = get_s_time();
     struct domain *d = v->domain;
@@ -2045,11 +2045,7 @@ void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp)
 
     spin_unlock(&d->arch.vtsc_lock);
 
-    msr_split(regs, gtime_to_gtsc(d, now));
-
-    if ( rdtscp )
-         regs->rcx =
-             (d->arch.tsc_mode == TSC_MODE_PVRDTSCP) ? d->arch.incarnation : 0;
+    return gtime_to_gtsc(d, now);
 }
 
 bool clocksource_is_tsc(void)

diff --git a/xen/include/asm-x86/time.h b/xen/include/asm-x86/time.h
index 046302ef199fb430c0f2a042a28d1ef1eebdbf1f..b3ae832df46157ea763a13a31fa36f8e6dce8687 100644 (file)
--- a/xen/include/asm-x86/time.h
+++ b/xen/include/asm-x86/time.h
@@ -56,7 +56,7 @@ uint64_t ns_to_acpi_pm_tick(uint64_t ns);
 
 uint64_t tsc_ticks2ns(uint64_t ticks);
 
-void pv_soft_rdtsc(struct vcpu *v, struct cpu_user_regs *regs, int rdtscp);
+uint64_t pv_soft_rdtsc(const struct vcpu *v, const struct cpu_user_regs *regs);
 u64 gtime_to_gtsc(struct domain *d, u64 time);
 u64 gtsc_to_gtime(struct domain *d, u64 tsc);