Merge hvm_store_cpu_guest_regs() and hvm_store_cpu_guest_ctrl_regs()

into a single function.

On VMX, make the function work even when the passed VCPU is not the
currently-executing VCPU.

This allows gdbserver-xen to get correct cpu register context for VMX guests.

Signed-off-by: Keir Fraser <keir@xensource.com>
Signed-off-by: Nitin A Kamble <nitin.a.kamble@intel.com>

7 files changed, 112 insertions, 78 deletions

diff --git a/xen/arch/x86/dom0_ops.c b/xen/arch/x86/dom0_ops.c
index cfb8eba348..ab76b4e9f5 100644
--- a/xen/arch/x86/dom0_ops.c
+++ b/xen/arch/x86/dom0_ops.c
@@ -460,8 +460,7 @@ void arch_getdomaininfo_ctxt(
 
     if ( hvm_guest(v) )
     {
-        hvm_store_cpu_guest_regs(v, &c->user_regs);
-        hvm_store_cpu_guest_ctrl_regs(v, c->ctrlreg);
+        hvm_store_cpu_guest_regs(v, &c->user_regs, c->ctrlreg);
     }
     else
     {
diff --git a/xen/arch/x86/hvm/platform.c b/xen/arch/x86/hvm/platform.c
index 4ae448ba39..94eb1fb13f 100644
--- a/xen/arch/x86/hvm/platform.c
+++ b/xen/arch/x86/hvm/platform.c
@@ -773,7 +773,7 @@ void handle_mmio(unsigned long va, unsigned long gpa)
     mmio_opp = &v->arch.hvm_vcpu.mmio_op;
 
     regs = mmio_opp->inst_decoder_regs;
-    hvm_store_cpu_guest_regs(v, regs);
+    hvm_store_cpu_guest_regs(v, regs, NULL);
 
     if ((inst_len = hvm_instruction_length(v)) <= 0) {
         printf("handle_mmio: failed to get instruction length\n");
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 42bda15b38..22a5bcb418 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -201,31 +201,41 @@ int svm_initialize_guest_resources(struct vcpu *v)
 }
 
 static void svm_store_cpu_guest_regs(
-    struct vcpu *v, struct cpu_user_regs *regs)
+    struct vcpu *v, struct cpu_user_regs *regs, unsigned long *crs)
 {
     struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
 
+    if ( regs != NULL )
+    {
 #if defined (__x86_64__)
-    regs->rip    = vmcb->rip;
-    regs->rsp    = vmcb->rsp;
-    regs->rflags = vmcb->rflags;
-    regs->cs     = vmcb->cs.sel;
-    regs->ds     = vmcb->ds.sel;
-    regs->es     = vmcb->es.sel;
-    regs->ss     = vmcb->ss.sel;
-    regs->gs     = vmcb->gs.sel;
-    regs->fs     = vmcb->fs.sel;
+        regs->rip    = vmcb->rip;
+        regs->rsp    = vmcb->rsp;
+        regs->rflags = vmcb->rflags;
+        regs->cs     = vmcb->cs.sel;
+        regs->ds     = vmcb->ds.sel;
+        regs->es     = vmcb->es.sel;
+        regs->ss     = vmcb->ss.sel;
+        regs->gs     = vmcb->gs.sel;
+        regs->fs     = vmcb->fs.sel;
 #elif defined (__i386__)
-    regs->eip    = vmcb->rip;
-    regs->esp    = vmcb->rsp;
-    regs->eflags = vmcb->rflags;
-    regs->cs     = vmcb->cs.sel;
-    regs->ds     = vmcb->ds.sel;
-    regs->es     = vmcb->es.sel;
-    regs->ss     = vmcb->ss.sel;
-    regs->gs     = vmcb->gs.sel;
-    regs->fs     = vmcb->fs.sel;
+        regs->eip    = vmcb->rip;
+        regs->esp    = vmcb->rsp;
+        regs->eflags = vmcb->rflags;
+        regs->cs     = vmcb->cs.sel;
+        regs->ds     = vmcb->ds.sel;
+        regs->es     = vmcb->es.sel;
+        regs->ss     = vmcb->ss.sel;
+        regs->gs     = vmcb->gs.sel;
+        regs->fs     = vmcb->fs.sel;
 #endif
+    }
+
+    if ( crs != NULL )
+    {
+        crs[0] = vmcb->cr0;
+        crs[3] = vmcb->cr3;
+        crs[4] = vmcb->cr4;
+    }
 }
 
 static void svm_load_cpu_guest_regs(
@@ -372,15 +382,6 @@ static inline int long_mode_do_msr_write(struct cpu_user_regs *regs)
     return 1;
 }
 
-void svm_store_cpu_guest_ctrl_regs(struct vcpu *v, unsigned long crs[8])
-{
-    struct vmcb_struct *vmcb = v->arch.hvm_svm.vmcb;
-
-    crs[0] = vmcb->cr0;
-    crs[3] = vmcb->cr3;
-    crs[4] = vmcb->cr4;
-}
-
 void svm_modify_guest_state(struct vcpu *v)
 {
     svm_modify_vmcb(v, &v->arch.guest_context.user_regs);
@@ -448,7 +449,6 @@ int start_svm(void)
     hvm_funcs.store_cpu_guest_regs = svm_store_cpu_guest_regs;
     hvm_funcs.load_cpu_guest_regs = svm_load_cpu_guest_regs;
 
-    hvm_funcs.store_cpu_guest_ctrl_regs = svm_store_cpu_guest_ctrl_regs;
     hvm_funcs.modify_guest_state = svm_modify_guest_state;
 
     hvm_funcs.realmode = svm_realmode;
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index fcca96efdb..69af5901dc 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -398,31 +398,81 @@ void vmx_migrate_timers(struct vcpu *v)
         migrate_timer(&(VLAPIC(v)->vlapic_timer), v->processor);
 }
 
-void vmx_store_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *regs)
+struct vmx_store_cpu_guest_regs_callback_info {
+    struct vcpu *v;
+    struct cpu_user_regs *regs;
+    unsigned long *crs;
+};
+
+static void vmx_store_cpu_guest_regs(
+    struct vcpu *v, struct cpu_user_regs *regs, unsigned long *crs);
+
+static void vmx_store_cpu_guest_regs_callback(void *data)
 {
+    struct vmx_store_cpu_guest_regs_callback_info *info = data;
+    vmx_store_cpu_guest_regs(info->v, info->regs, info->crs);
+}
+
+static void vmx_store_cpu_guest_regs(
+    struct vcpu *v, struct cpu_user_regs *regs, unsigned long *crs)
+{
+    if ( v != current )
+    {
+        /* Non-current VCPUs must be paused to get a register snapshot. */
+        ASSERT(atomic_read(&v->pausecnt) != 0);
+
+        if ( v->arch.hvm_vmx.launch_cpu != smp_processor_id() )
+        {
+            /* Get register details from remote CPU. */
+            struct vmx_store_cpu_guest_regs_callback_info info = {
+                .v = v, .regs = regs, .crs = crs };
+            cpumask_t cpumask = cpumask_of_cpu(v->arch.hvm_vmx.launch_cpu);
+            on_selected_cpus(cpumask, vmx_store_cpu_guest_regs_callback,
+                             &info, 1, 1);
+            return;
+        }
+
+        /* Register details are on this CPU. Load the correct VMCS. */
+        __vmptrld(virt_to_maddr(v->arch.hvm_vmx.vmcs));
+    }
+
+    ASSERT(v->arch.hvm_vmx.launch_cpu == smp_processor_id());
+
+    if ( regs != NULL )
+    {
 #if defined (__x86_64__)
-    __vmread(GUEST_RFLAGS, &regs->rflags);
-    __vmread(GUEST_SS_SELECTOR, &regs->ss);
-    __vmread(GUEST_CS_SELECTOR, &regs->cs);
-    __vmread(GUEST_DS_SELECTOR, &regs->ds);
-    __vmread(GUEST_ES_SELECTOR, &regs->es);
-    __vmread(GUEST_GS_SELECTOR, &regs->gs);
-    __vmread(GUEST_FS_SELECTOR, &regs->fs);
-    __vmread(GUEST_RIP, &regs->rip);
-    __vmread(GUEST_RSP, &regs->rsp);
+        __vmread(GUEST_RFLAGS, &regs->rflags);
+        __vmread(GUEST_SS_SELECTOR, &regs->ss);
+        __vmread(GUEST_CS_SELECTOR, &regs->cs);
+        __vmread(GUEST_DS_SELECTOR, &regs->ds);
+        __vmread(GUEST_ES_SELECTOR, &regs->es);
+        __vmread(GUEST_GS_SELECTOR, &regs->gs);
+        __vmread(GUEST_FS_SELECTOR, &regs->fs);
+        __vmread(GUEST_RIP, &regs->rip);
+        __vmread(GUEST_RSP, &regs->rsp);
 #elif defined (__i386__)
-    __vmread(GUEST_RFLAGS, &regs->eflags);
-    __vmread(GUEST_SS_SELECTOR, &regs->ss);
-    __vmread(GUEST_CS_SELECTOR, &regs->cs);
-    __vmread(GUEST_DS_SELECTOR, &regs->ds);
-    __vmread(GUEST_ES_SELECTOR, &regs->es);
-    __vmread(GUEST_GS_SELECTOR, &regs->gs);
-    __vmread(GUEST_FS_SELECTOR, &regs->fs);
-    __vmread(GUEST_RIP, &regs->eip);
-    __vmread(GUEST_RSP, &regs->esp);
-#else
-#error Unsupported architecture
+        __vmread(GUEST_RFLAGS, &regs->eflags);
+        __vmread(GUEST_SS_SELECTOR, &regs->ss);
+        __vmread(GUEST_CS_SELECTOR, &regs->cs);
+        __vmread(GUEST_DS_SELECTOR, &regs->ds);
+        __vmread(GUEST_ES_SELECTOR, &regs->es);
+        __vmread(GUEST_GS_SELECTOR, &regs->gs);
+        __vmread(GUEST_FS_SELECTOR, &regs->fs);
+        __vmread(GUEST_RIP, &regs->eip);
+        __vmread(GUEST_RSP, &regs->esp);
 #endif
+    }
+
+    if ( crs != NULL )
+    {
+        __vmread(CR0_READ_SHADOW, &crs[0]);
+        __vmread(GUEST_CR3, &crs[3]);
+        __vmread(CR4_READ_SHADOW, &crs[4]);
+    }
+
+    /* Reload current VCPU's VMCS if it was temporarily unloaded. */
+    if ( (v != current) && hvm_guest(current) )
+        __vmptrld(virt_to_maddr(current->arch.hvm_vmx.vmcs));
 }
 
 void vmx_load_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *regs)
@@ -456,13 +506,6 @@ void vmx_load_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *regs)
 #endif
 }
 
-void vmx_store_cpu_guest_ctrl_regs(struct vcpu *v, unsigned long crs[8])
-{
-    __vmread(CR0_READ_SHADOW, &crs[0]);
-    __vmread(GUEST_CR3, &crs[3]);
-    __vmread(CR4_READ_SHADOW, &crs[4]);
-}
-
 void vmx_modify_guest_state(struct vcpu *v)
 {
     modify_vmcs(&v->arch.hvm_vmx, &v->arch.guest_context.user_regs);
@@ -616,7 +659,6 @@ int start_vmx(void)
     hvm_funcs.store_cpu_guest_regs = vmx_store_cpu_guest_regs;
     hvm_funcs.load_cpu_guest_regs = vmx_load_cpu_guest_regs;
 
-    hvm_funcs.store_cpu_guest_ctrl_regs = vmx_store_cpu_guest_ctrl_regs;
     hvm_funcs.modify_guest_state = vmx_modify_guest_state;
 
     hvm_funcs.realmode = vmx_realmode;
diff --git a/xen/arch/x86/x86_32/traps.c b/xen/arch/x86/x86_32/traps.c
index 6fc271867c..1c570dad29 100644
--- a/xen/arch/x86/x86_32/traps.c
+++ b/xen/arch/x86/x86_32/traps.c
@@ -27,8 +27,7 @@ void show_registers(struct cpu_user_regs *regs)
     if ( hvm_guest(current) && guest_mode(regs) )
     {
         context = "hvm";
-        hvm_store_cpu_guest_regs(current, &fault_regs);
-        hvm_store_cpu_guest_ctrl_regs(current, fault_crs);
+        hvm_store_cpu_guest_regs(current, &fault_regs, fault_crs);
     }
     else
     {
diff --git a/xen/arch/x86/x86_64/traps.c b/xen/arch/x86/x86_64/traps.c
index ef1f21cb09..e78c8f9453 100644
--- a/xen/arch/x86/x86_64/traps.c
+++ b/xen/arch/x86/x86_64/traps.c
@@ -27,8 +27,7 @@ void show_registers(struct cpu_user_regs *regs)
     if ( hvm_guest(current) && guest_mode(regs) )
     {
         context = "hvm";
-        hvm_store_cpu_guest_regs(current, &fault_regs);
-        hvm_store_cpu_guest_ctrl_regs(current, fault_crs);
+        hvm_store_cpu_guest_regs(current, &fault_regs, fault_crs);
     }
     else
     {
diff --git a/xen/include/asm-x86/hvm/hvm.h b/xen/include/asm-x86/hvm/hvm.h
index 70af33035b..eff373996c 100644
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -41,12 +41,12 @@ struct hvm_function_table {
     /*
      * Store and load guest state:
      * 1) load/store guest register state,
-     * 2) store guest control register state (used for panic dumps),
-     * 3) modify guest state (e.g., set debug flags).
+     * 2) modify guest state (e.g., set debug flags).
      */
-    void (*store_cpu_guest_regs)(struct vcpu *v, struct cpu_user_regs *r);
-    void (*load_cpu_guest_regs)(struct vcpu *v, struct cpu_user_regs *r);
-    void (*store_cpu_guest_ctrl_regs)(struct vcpu *v, unsigned long crs[8]);
+    void (*store_cpu_guest_regs)(
+        struct vcpu *v, struct cpu_user_regs *r, unsigned long *crs);
+    void (*load_cpu_guest_regs)(
+        struct vcpu *v, struct cpu_user_regs *r);
     void (*modify_guest_state)(struct vcpu *v);
 
     /*
@@ -93,9 +93,10 @@ hvm_relinquish_guest_resources(struct domain *d)
 }
 
 static inline void
-hvm_store_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *r)
+hvm_store_cpu_guest_regs(
+    struct vcpu *v, struct cpu_user_regs *r, unsigned long *crs)
 {
-    hvm_funcs.store_cpu_guest_regs(v, r);
+    hvm_funcs.store_cpu_guest_regs(v, r, crs);
 }
 
 static inline void
@@ -105,12 +106,6 @@ hvm_load_cpu_guest_regs(struct vcpu *v, struct cpu_user_regs *r)
 }
 
 static inline void
-hvm_store_cpu_guest_ctrl_regs(struct vcpu *v, unsigned long crs[8])
-{
-    hvm_funcs.store_cpu_guest_ctrl_regs(v, crs);
-}
-
-static inline void
 hvm_modify_guest_state(struct vcpu *v)
 {
     hvm_funcs.modify_guest_state(v);