[Xen-devel] [PATCH 1/3] x86/hvm: don't use indirect calls without need

["Jan Beulich" <JBeulich@xxxxxxxx>]

Direct calls perform better, so we should prefer them and use indirect
ones only when there indeed is a need for indirection.

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

--- a/xen/arch/x86/apic.c
+++ b/xen/arch/x86/apic.c
@@ -1373,7 +1373,7 @@ void error_interrupt(struct cpu_user_reg
 void pmu_apic_interrupt(struct cpu_user_regs *regs)
 {
     ack_APIC_irq();
-    hvm_do_pmu_interrupt(regs);
+    vpmu_do_interrupt(regs);
 }
 
 /*
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -73,6 +73,8 @@ bool_t cpu_has_lmsl;
 #define set_segment_register(name, value)  \
     asm volatile ( "movw %%ax ,%%" STR(name) "" : : "a" (value) )
 
+static void svm_update_guest_efer(struct vcpu *);
+
 static struct hvm_function_table svm_function_table;
 
 /* va of hardware host save area     */
@@ -269,9 +271,9 @@ static int svm_vmcb_restore(struct vcpu 
     v->arch.hvm_vcpu.guest_cr[2] = c->cr2;
     v->arch.hvm_vcpu.guest_cr[3] = c->cr3;
     v->arch.hvm_vcpu.guest_cr[4] = c->cr4;
-    hvm_update_guest_cr(v, 0);
-    hvm_update_guest_cr(v, 2);
-    hvm_update_guest_cr(v, 4);
+    svm_update_guest_cr(v, 0);
+    svm_update_guest_cr(v, 2);
+    svm_update_guest_cr(v, 4);
 
     /* Load sysenter MSRs into both VMCB save area and VCPU fields. */
     vmcb->sysenter_cs = v->arch.hvm_svm.guest_sysenter_cs = c->sysenter_cs;
@@ -330,7 +332,7 @@ static void svm_load_cpu_state(struct vc
     vmcb->cstar      = data->msr_cstar;
     vmcb->sfmask     = data->msr_syscall_mask;
     v->arch.hvm_vcpu.guest_efer = data->msr_efer;
-    hvm_update_guest_efer(v);
+    svm_update_guest_efer(v);
 
     hvm_set_guest_tsc(v, data->tsc);
 }
@@ -426,12 +428,7 @@ static int svm_guest_x86_mode(struct vcp
     return (likely(vmcb->cs.attr.fields.db) ? 4 : 2);
 }
 
-static void svm_update_host_cr3(struct vcpu *v)
-{
-    /* SVM doesn't have a HOST_CR3 equivalent to update. */
-}
-
-static void svm_update_guest_cr(struct vcpu *v, unsigned int cr)
+void svm_update_guest_cr(struct vcpu *v, unsigned int cr)
 {
     struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
     uint64_t value;
@@ -1128,11 +1125,6 @@ static int svm_event_pending(struct vcpu
     return vmcb->eventinj.fields.v;
 }
 
-static int svm_do_pmu_interrupt(struct cpu_user_regs *regs)
-{
-    return vpmu_do_interrupt(regs);
-}
-
 static void svm_cpu_dead(unsigned int cpu)
 {
     free_xenheap_page(per_cpu(hsa, cpu));
@@ -1997,7 +1989,6 @@ static struct hvm_function_table __read_
     .get_segment_register = svm_get_segment_register,
     .set_segment_register = svm_set_segment_register,
     .get_shadow_gs_base   = svm_get_shadow_gs_base,
-    .update_host_cr3      = svm_update_host_cr3,
     .update_guest_cr      = svm_update_guest_cr,
     .update_guest_efer    = svm_update_guest_efer,
     .set_guest_pat        = svm_set_guest_pat,
@@ -2006,7 +1997,6 @@ static struct hvm_function_table __read_
     .inject_trap          = svm_inject_trap,
     .init_hypercall_page  = svm_init_hypercall_page,
     .event_pending        = svm_event_pending,
-    .do_pmu_interrupt     = svm_do_pmu_interrupt,
     .cpuid_intercept      = svm_cpuid_intercept,
     .wbinvd_intercept     = svm_wbinvd_intercept,
     .fpu_dirty_intercept  = svm_fpu_dirty_intercept,
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -709,8 +709,8 @@ static void vmx_ctxt_switch_to(struct vc
         .fields = { .type = 0xb, .s = 0, .dpl = 0, .p = 1, .avl = 0,    \
                     .l = 0, .db = 0, .g = 0, .pad = 0 } }).bytes)
 
-static void vmx_get_segment_register(struct vcpu *v, enum x86_segment seg,
-                                     struct segment_register *reg)
+void vmx_get_segment_register(struct vcpu *v, enum x86_segment seg,
+                              struct segment_register *reg)
 {
     uint32_t attr = 0;
 
@@ -1461,11 +1461,6 @@ static int vmx_event_pending(struct vcpu
     return (__vmread(VM_ENTRY_INTR_INFO) & INTR_INFO_VALID_MASK);
 }
 
-static int vmx_do_pmu_interrupt(struct cpu_user_regs *regs)
-{
-    return vpmu_do_interrupt(regs);
-}
-
 static void vmx_set_uc_mode(struct vcpu *v)
 {
     if ( paging_mode_hap(v->domain) )
@@ -1527,7 +1522,6 @@ static struct hvm_function_table __read_
     .inject_trap          = vmx_inject_trap,
     .init_hypercall_page  = vmx_init_hypercall_page,
     .event_pending        = vmx_event_pending,
-    .do_pmu_interrupt     = vmx_do_pmu_interrupt,
     .cpu_up               = vmx_cpu_up,
     .cpu_down             = vmx_cpu_down,
     .cpuid_intercept      = vmx_cpuid_intercept,
@@ -1642,7 +1636,7 @@ static void vmx_cpuid_intercept(
     {
         case 0x80000001:
             /* SYSCALL is visible iff running in long mode. */
-            hvm_get_segment_register(v, x86_seg_cs, &cs);
+            vmx_get_segment_register(v, x86_seg_cs, &cs);
             if ( cs.attr.fields.l )
                 *edx |= cpufeat_mask(X86_FEATURE_SYSCALL);
             else
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -291,8 +291,6 @@ static int vmx_inst_check_privilege(stru
     struct vcpu *v = current;
     struct segment_register cs;
 
-    hvm_get_segment_register(v, x86_seg_cs, &cs);
-
     if ( vmxop_check )
     {
         if ( !(v->arch.hvm_vcpu.guest_cr[0] & X86_CR0_PE) ||
@@ -302,6 +300,8 @@ static int vmx_inst_check_privilege(stru
     else if ( !vcpu_2_nvmx(v).vmxon_region_pa )
         goto invalid_op;
 
+    vmx_get_segment_register(v, x86_seg_cs, &cs);
+
     if ( (regs->eflags & X86_EFLAGS_VM) ||
          (hvm_long_mode_enabled(v) && cs.attr.fields.l == 0) )
         goto invalid_op;
@@ -358,13 +358,13 @@ static int decode_vmx_inst(struct cpu_us
 
         if ( hvm_long_mode_enabled(v) )
         {
-            hvm_get_segment_register(v, x86_seg_cs, &seg);
+            vmx_get_segment_register(v, x86_seg_cs, &seg);
             mode_64bit = seg.attr.fields.l;
         }
 
         if ( info.fields.segment > VMX_SREG_GS )
             goto gp_fault;
-        hvm_get_segment_register(v, sreg_to_index[info.fields.segment], &seg);
+        vmx_get_segment_register(v, sreg_to_index[info.fields.segment], &seg);
         seg_base = seg.base;
 
         base = info.fields.base_reg_invalid ? 0 :
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -137,7 +137,6 @@ struct hvm_function_table {
     void (*init_hypercall_page)(struct domain *d, void *hypercall_page);
 
     int  (*event_pending)(struct vcpu *v);
-    int  (*do_pmu_interrupt)(struct cpu_user_regs *regs);
 
     int  (*cpu_up_prepare)(unsigned int cpu);
     void (*cpu_dead)(unsigned int cpu);
@@ -270,7 +269,8 @@ hvm_guest_x86_mode(struct vcpu *v)
 static inline void
 hvm_update_host_cr3(struct vcpu *v)
 {
-    hvm_funcs.update_host_cr3(v);
+    if ( hvm_funcs.update_host_cr3 )
+        hvm_funcs.update_host_cr3(v);
 }
 
 static inline void hvm_update_guest_cr(struct vcpu *v, unsigned int cr)
@@ -334,11 +334,6 @@ static inline int hvm_event_pending(stru
     return hvm_funcs.event_pending(v);
 }
 
-static inline int hvm_do_pmu_interrupt(struct cpu_user_regs *regs)
-{
-    return hvm_funcs.do_pmu_interrupt(regs);
-}
-
 /* These reserved bits in lower 32 remain 0 after any load of CR0 */
 #define HVM_CR0_GUEST_RESERVED_BITS             \
     (~((unsigned long)                          \
--- a/xen/include/asm-x86/hvm/svm/svm.h
+++ b/xen/include/asm-x86/hvm/svm/svm.h
@@ -66,6 +66,7 @@ static inline void svm_invlpga(unsigned 
 
 unsigned long *svm_msrbit(unsigned long *msr_bitmap, uint32_t msr);
 void __update_guest_eip(struct cpu_user_regs *regs, unsigned int inst_len);
+void svm_update_guest_cr(struct vcpu *, unsigned int cr);
 
 extern u32 svm_feature_flags;
 
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -387,6 +387,8 @@ static inline int __vmxon(u64 addr)
     return rc;
 }
 
+void vmx_get_segment_register(struct vcpu *, enum x86_segment,
+                              struct segment_register *);
 void vmx_inject_extint(int trap);
 void vmx_inject_nmi(void);

Attachment: hvm-no-indirect-calls.patch
Description: Text document

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