[patch 09/15] x86: kvm guest: pvclock vsyscall support

[Marcelo Tosatti]

Allow hypervisor to update userspace visible copy of
pvclock data.

Signed-off-by: Marcelo Tosatti <mtosa...@redhat.com>

Index: vsyscall/arch/x86/kernel/kvmclock.c
===================================================================
--- vsyscall.orig/arch/x86/kernel/kvmclock.c
+++ vsyscall/arch/x86/kernel/kvmclock.c
@@ -31,6 +31,9 @@ static int kvmclock = 1;
 static int msr_kvm_system_time = MSR_KVM_SYSTEM_TIME;
 static int msr_kvm_wall_clock = MSR_KVM_WALL_CLOCK;
 
+/* set when the generic vsyscall pvclock elements are setup */
+bool vsyscall_clock_initializable = false;
+
 static int parse_no_kvmclock(char *arg)
 {
        kvmclock = 0;
@@ -151,6 +154,28 @@ int kvm_register_clock(char *txt)
        return ret;
 }
 
+static int kvm_register_vsyscall_clock(char *txt)
+{
+#ifdef CONFIG_PARAVIRT_CLOCK_VSYSCALL
+       int cpu = smp_processor_id();
+       int low, high, ret;
+       struct pvclock_vcpu_time_info *info;
+
+       info = pvclock_get_vsyscall_time_info(cpu);
+
+       low = (int)__pa(info) | 1;
+       high = ((u64)__pa(&per_cpu(hv_clock, cpu)) >> 32);
+       ret = native_write_msr_safe(MSR_KVM_USERSPACE_TIME, low, high);
+       printk(KERN_INFO "kvm-clock: cpu %d, msr %x:%x, %s\n",
+              cpu, high, low, txt);
+
+       return ret;
+#else
+       return 0;
+#endif
+}
+
+
 static void kvm_save_sched_clock_state(void)
 {
 }
@@ -158,6 +183,8 @@ static void kvm_save_sched_clock_state(v
 static void kvm_restore_sched_clock_state(void)
 {
        kvm_register_clock("primary cpu clock, resume");
+       if (vsyscall_clock_initializable)
+               kvm_register_vsyscall_clock("primary cpu vsyscall clock, 
resume");
 }
 
 #ifdef CONFIG_X86_LOCAL_APIC
@@ -168,6 +195,8 @@ static void __cpuinit kvm_setup_secondar
         * we shouldn't fail.
         */
        WARN_ON(kvm_register_clock("secondary cpu clock"));
+       if (vsyscall_clock_initializable)
+               kvm_register_vsyscall_clock("secondary cpu vsyscall clock");
 }
 #endif
 
@@ -182,6 +211,8 @@ static void __cpuinit kvm_setup_secondar
 #ifdef CONFIG_KEXEC
 static void kvm_crash_shutdown(struct pt_regs *regs)
 {
+       if (vsyscall_clock_initializable)
+               native_write_msr(MSR_KVM_USERSPACE_TIME, 0, 0);
        native_write_msr(msr_kvm_system_time, 0, 0);
        kvm_disable_steal_time();
        native_machine_crash_shutdown(regs);
@@ -190,6 +221,8 @@ static void kvm_crash_shutdown(struct pt
 
 static void kvm_shutdown(void)
 {
+       if (vsyscall_clock_initializable)
+               native_write_msr(MSR_KVM_USERSPACE_TIME, 0, 0);
        native_write_msr(msr_kvm_system_time, 0, 0);
        kvm_disable_steal_time();
        native_machine_shutdown();
@@ -233,3 +266,27 @@ void __init kvmclock_init(void)
        if (kvm_para_has_feature(KVM_FEATURE_CLOCKSOURCE_STABLE_BIT))
                pvclock_set_flags(PVCLOCK_TSC_STABLE_BIT);
 }
+
+int kvm_setup_vsyscall_timeinfo(void)
+{
+#ifdef CONFIG_PARAVIRT_CLOCK_VSYSCALL
+       int ret;
+       struct pvclock_vcpu_time_info *vcpu_time;
+       u8 flags;
+
+       vcpu_time = &get_cpu_var(hv_clock);
+       flags = pvclock_read_flags(vcpu_time);
+       put_cpu_var(hv_clock);
+
+       if (!(flags & PVCLOCK_TSC_STABLE_BIT))
+               return 1;
+
+       if ((ret = pvclock_init_vsyscall()))
+               return ret;
+
+       kvm_clock.archdata.vclock_mode = VCLOCK_PVCLOCK;
+       vsyscall_clock_initialized = true;
+#endif /* CONFIG_PARAVIRT_CLOCK_VSYSCALL */
+       return 0;
+}
+
Index: vsyscall/arch/x86/kernel/kvm.c
===================================================================
--- vsyscall.orig/arch/x86/kernel/kvm.c
+++ vsyscall/arch/x86/kernel/kvm.c
@@ -42,6 +42,7 @@
 #include <asm/apic.h>
 #include <asm/apicdef.h>
 #include <asm/hypervisor.h>
+#include <asm/kvm_guest.h>
 
 static int kvmapf = 1;
 
@@ -468,6 +469,9 @@ void __init kvm_guest_init(void)
        if (kvm_para_has_feature(KVM_FEATURE_PV_EOI))
                apic_set_eoi_write(kvm_guest_apic_eoi_write);
 
+       if (kvm_para_has_feature(KVM_FEATURE_USERSPACE_CLOCKSOURCE))
+               kvm_setup_vsyscall_timeinfo();
+
 #ifdef CONFIG_SMP
        smp_ops.smp_prepare_boot_cpu = kvm_smp_prepare_boot_cpu;
        register_cpu_notifier(&kvm_cpu_notifier);
Index: vsyscall/arch/x86/include/asm/kvm_guest.h
===================================================================
--- /dev/null
+++ vsyscall/arch/x86/include/asm/kvm_guest.h
@@ -0,0 +1,8 @@
+#ifndef _ASM_X86_KVM_GUEST_H
+#define _ASM_X86_KVM_GUEST_H
+
+extern bool vsyscall_clock_initializable;
+
+int kvm_setup_vsyscall_timeinfo(void);
+
+#endif /* _ASM_X86_KVM_GUEST_H */


--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html