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From 62ac85ec7c8e41b0454bdec0e0a9c7d5adc39280 Mon Sep 17 00:00:00 2001
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From: "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>
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Date: Wed, 22 Oct 2014 09:46:34 +0200
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Subject: [PATCH 3/6] Revert "kvmclock: Ensure time in migration never goes
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 backward"
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Message-id: <1413971197-4624-3-git-send-email-dgilbert@redhat.com>
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Patchwork-id: 61788
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O-Subject: [RHEL-7.1 qemu-kvm PATCH 2/5] Revert "kvmclock: Ensure time in migration never goes backward"
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Bugzilla: 1098602 1130428
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RH-Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
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RH-Acked-by: Eduardo Habkost <ehabkost@redhat.com>
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RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>
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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
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This reverts commit 4b6035c2a739bc4c086abbb36f0883a1178a8f1c.
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The equivalent upstream revert is Paolo's fa666c10f2f3e15685ff
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Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
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---
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 hw/i386/kvm/clock.c | 49 -------------------------------------------------
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 1 file changed, 49 deletions(-)
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diff --git a/hw/i386/kvm/clock.c b/hw/i386/kvm/clock.c
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index 1f2a26e..6d6f3a7 100644
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--- a/hw/i386/kvm/clock.c
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+++ b/hw/i386/kvm/clock.c
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@@ -14,7 +14,6 @@
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  */
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 #include "qemu-common.h"
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-#include "qemu/host-utils.h"
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 #include "sysemu/sysemu.h"
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 #include "sysemu/kvm.h"
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 #include "hw/sysbus.h"
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@@ -29,48 +28,6 @@ typedef struct KVMClockState {
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     bool clock_valid;
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 } KVMClockState;
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-struct pvclock_vcpu_time_info {
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-    uint32_t   version;
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-    uint32_t   pad0;
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-    uint64_t   tsc_timestamp;
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-    uint64_t   system_time;
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-    uint32_t   tsc_to_system_mul;
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-    int8_t     tsc_shift;
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-    uint8_t    flags;
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-    uint8_t    pad[2];
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-} __attribute__((__packed__)); /* 32 bytes */
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-
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-static uint64_t kvmclock_current_nsec(KVMClockState *s)
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-{
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-    CPUArchState *acpu = first_cpu;
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-    CPUState *cpu = ENV_GET_CPU(acpu);
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-    CPUX86State *env = cpu->env_ptr;
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-    hwaddr kvmclock_struct_pa = env->system_time_msr & ~1ULL;
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-    uint64_t migration_tsc = env->tsc;
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-    struct pvclock_vcpu_time_info time;
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-    uint64_t delta;
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-    uint64_t nsec_lo;
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-    uint64_t nsec_hi;
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-    uint64_t nsec;
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-
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-    if (!(env->system_time_msr & 1ULL)) {
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-        /* KVM clock not active */
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-        return 0;
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-    }
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-
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-    cpu_physical_memory_read(kvmclock_struct_pa, &time, sizeof(time));
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-
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-    delta = migration_tsc - time.tsc_timestamp;
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-    if (time.tsc_shift < 0) {
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-        delta >>= -time.tsc_shift;
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-    } else {
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-        delta <<= time.tsc_shift;
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-    }
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-
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-    mulu64(&nsec_lo, &nsec_hi, delta, time.tsc_to_system_mul);
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-    nsec = (nsec_lo >> 32) | (nsec_hi << 32);
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-    return nsec + time.system_time;
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-}
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 static void kvmclock_vm_state_change(void *opaque, int running,
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                                      RunState state)
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@@ -82,15 +39,9 @@ static void kvmclock_vm_state_change(void *opaque, int running,
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     if (running) {
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         struct kvm_clock_data data;
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-        uint64_t time_at_migration = kvmclock_current_nsec(s);
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         s->clock_valid = false;
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-	/* We can't rely on the migrated clock value, just discard it */
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-	if (time_at_migration) {
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-	        s->clock = time_at_migration;
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-	}
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-
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         data.clock = s->clock;
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         data.flags = 0;
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         ret = kvm_vm_ioctl(kvm_state, KVM_SET_CLOCK, &data);
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-- 
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1.8.3.1
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