Re: [Qemu-devel] [PATCH 2/2] Qemu co-operation with kvm tsc deadline timer

[Marcelo Tosatti]

On Wed, Sep 14, 2011 at 10:51:41AM +0800, Liu, Jinsong wrote:
> Jan Kiszka wrote:
> > On 2011-09-13 16:38, Liu, Jinsong wrote:
> >> From c1b502d6548fcc41592cd90acc82109ee949df75 Mon Sep 17 00:00:00
> >> 2001 
> >> From: Liu, Jinsong <address@hidden>
> >> Date: Tue, 13 Sep 2011 22:05:30 +0800
> >> Subject: [PATCH] Qemu co-operation with kvm tsc deadline timer
> >> 
> >> KVM add emulation of lapic tsc deadline timer for guest.
> >> This patch is co-operation work at qemu side.
> >> 
> >> Signed-off-by: Liu, Jinsong <address@hidden> ---
> >>  target-i386/cpu.h |    2 ++
> >>  target-i386/kvm.c |   14 ++++++++++++++
> >>  2 files changed, 16 insertions(+), 0 deletions(-)
> >> 
> >> diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> >> index 935d08a..62ff73c 100644
> >> --- a/target-i386/cpu.h
> >> +++ b/target-i386/cpu.h
> >> @@ -283,6 +283,7 @@
> >>  #define MSR_IA32_APICBASE_BSP           (1<<8)
> >>  #define MSR_IA32_APICBASE_ENABLE        (1<<11)
> >>  #define MSR_IA32_APICBASE_BASE          (0xfffff<<12)
> >> +#define MSR_IA32_TSCDEADLINE            0x6e0
> >> 
> >>  #define MSR_MTRRcap                       0xfe
> >>  #define MSR_MTRRcap_VCNT          8
> >> @@ -687,6 +688,7 @@ typedef struct CPUX86State {
> >>      uint64_t async_pf_en_msr;
> >> 
> >>      uint64_t tsc;
> >> +    uint64_t tsc_deadline;
> > 
> > This field has to be saved/restored for snapshots/migrations.
> > 
> > Frankly, I've no clue right now if substates are in vogue again (they
> > had problems in their binary format) or if you can simply add a
> > versioned top-level field and bump the CPUState version number.
> > 
> 
> Yes, it would be saved/restored. After migration, tsc_deadline would be set 
> to MSR_IA32_TSCDEADLINE to trigger tsc timer interrupt.

Jan means you should explicitly add this to machine.c.