Re: [Qemu-devel] [PATCHv2] qemu: enable PV EOI for qemu 1.3

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Oct 18, 2012 at 04:13:38PM +0200, Andreas Färber wrote:
> Am 18.10.2012 00:15, schrieb Michael S. Tsirkin:
> > Enable KVM PV EOI by default. You can still disable it with
> > -kvm_pv_eoi cpu flag. To avoid breaking cross-version migration,
> > enable only for qemu 1.3 (or in the future, newer) machine type.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> > 
> > Changes from v1:
> >     Address comments by Eduardo:
> >         use include instead of duplicate definition
> >         reduce ifdef spagetti in code using features mask
> >         rename init from _pv_eoi to _1_3 to enable adding
> >         more stuff in this version
> > 
> >  hw/pc_piix.c      | 15 ++++++++++++++-
> >  target-i386/cpu.c | 33 ++++++++++++++++++++-------------
> >  target-i386/cpu.h |  2 ++
> >  3 files changed, 36 insertions(+), 14 deletions(-)
> > 
> > diff --git a/hw/pc_piix.c b/hw/pc_piix.c
> > index 82364ab..607de77 100644
> > --- a/hw/pc_piix.c
> > +++ b/hw/pc_piix.c
> > @@ -43,6 +43,7 @@
> >  #include "xen.h"
> >  #include "memory.h"
> >  #include "exec-memory.h"
> > +#include "cpu.h"
> >  #ifdef CONFIG_XEN
> >  #  include <xen/hvm/hvm_info_table.h>
> >  #endif
> > @@ -301,6 +302,18 @@ static void pc_init_pci(ram_addr_t ram_size,
> >               initrd_filename, cpu_model, 1, 1);
> >  }
> >  
> > +static void pc_init_pci_1_3(ram_addr_t ram_size,
> > +                               const char *boot_device,
> > +                               const char *kernel_filename,
> > +                               const char *kernel_cmdline,
> > +                               const char *initrd_filename,
> > +                               const char *cpu_model)
> 
> Indentation was not adapted to name change?
> 
> > +{
> > +    enable_kvm_pv_eoi();
> > +    pc_init_pci(ram_size, boot_device, kernel_filename,
> > +		kernel_cmdline, initrd_filename, cpu_model);
> 
> There's two tabs here.
> 
> Thought you wanted to s/pc_init_pci/pc_init_pci_1_2/g and name this
> pc_init_pci()?

I decided it's not worth it - better keep the patch small.

> Are you expecting there to be a pc_init_pci_1_4()?

I don't know. Maybe we will be able to stick to .. _1_3 for the
next 10 revisions.

> > +}
> > +
> >  static void pc_init_pci_no_kvmclock(ram_addr_t ram_size,
> >                                      const char *boot_device,
> >                                      const char *kernel_filename,
> > @@ -353,7 +366,7 @@ static QEMUMachine pc_machine_v1_3 = {
> >      .name = "pc-1.3",
> >      .alias = "pc",
> >      .desc = "Standard PC",
> > -    .init = pc_init_pci,
> > +    .init = pc_init_pci_1_3,
> >      .max_cpus = 255,
> >      .is_default = 1,
> >  };
> > diff --git a/target-i386/cpu.c b/target-i386/cpu.c
> > index f3708e6..5f316b3 100644
> > --- a/target-i386/cpu.c
> > +++ b/target-i386/cpu.c
> > @@ -124,6 +124,20 @@ typedef struct model_features_t {
> >  int check_cpuid = 0;
> >  int enforce_cpuid = 0;
> >  
> > +#if defined(CONFIG_KVM)
> > +static uint32_t kvm_default_features = (1 << KVM_FEATURE_CLOCKSOURCE) |
> > +        (1 << KVM_FEATURE_NOP_IO_DELAY) | 
> > +        (1 << KVM_FEATURE_MMU_OP) |
> > +        (1 << KVM_FEATURE_CLOCKSOURCE2) |
> > +        (1 << KVM_FEATURE_ASYNC_PF) | 
> > +        (1 << KVM_FEATURE_STEAL_TIME) |
> > +        (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
> > +static const uint32_t kvm_pv_eoi_features = (0x1 << KVM_FEATURE_PV_EOI);
> > +#else
> > +static uint32_t kvm_default_features = 0;
> > +static const uint32_t kvm_pv_eoi_features = 0;
> > +#endif
> > +
> >  void host_cpuid(uint32_t function, uint32_t count,
> >                  uint32_t *eax, uint32_t *ebx, uint32_t *ecx, uint32_t *edx)
> >  {
> > @@ -1107,7 +1121,7 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
> >      /* Features to be added*/
> >      uint32_t plus_features = 0, plus_ext_features = 0;
> >      uint32_t plus_ext2_features = 0, plus_ext3_features = 0;
> > -    uint32_t plus_kvm_features = 0, plus_svm_features = 0;
> > +    uint32_t plus_kvm_features = kvm_default_features, plus_svm_features = 0;
> >      uint32_t plus_7_0_ebx_features = 0;
> >      /* Features to be removed */
> >      uint32_t minus_features = 0, minus_ext_features = 0;
> > @@ -1127,18 +1141,6 @@ static int cpu_x86_find_by_name(x86_def_t *x86_cpu_def, const char *cpu_model)
> >          memcpy(x86_cpu_def, def, sizeof(*def));
> >      }
> >  
> > -#if defined(CONFIG_KVM)
> > -    plus_kvm_features = (1 << KVM_FEATURE_CLOCKSOURCE) |
> > -        (1 << KVM_FEATURE_NOP_IO_DELAY) | 
> > -        (1 << KVM_FEATURE_MMU_OP) |
> > -        (1 << KVM_FEATURE_CLOCKSOURCE2) |
> > -        (1 << KVM_FEATURE_ASYNC_PF) | 
> > -        (1 << KVM_FEATURE_STEAL_TIME) |
> > -        (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);
> > -#else
> > -    plus_kvm_features = 0;
> > -#endif
> > -
> >      add_flagname_to_bitmaps("hypervisor", &plus_features,
> >              &plus_ext_features, &plus_ext2_features, &plus_ext3_features,
> >              &plus_kvm_features, &plus_svm_features,  &plus_7_0_ebx_features);
> > @@ -1953,3 +1955,8 @@ static void x86_cpu_register_types(void)
> >  }
> >  
> >  type_init(x86_cpu_register_types)
> > +
> > +void enable_kvm_pv_eoi(void)
> > +{
> > +       kvm_default_features |= kvm_pv_eoi_features;
> > +}
> 
> Indentation is off (7 spaces).
> 
> I'd prefer to place this function below the variable definitions, so
> that type_init() remains at the bottom of the file.
> 
> Otherwise I'm happy with the modified cpu.h-based interaction.
> So far there's no conflicts here, so it could go through either PC
> maintainer, kvm/uq or qom-cpu.
> 
> Andreas
> 
> > diff --git a/target-i386/cpu.h b/target-i386/cpu.h
> > index 871c270..de33303 100644
> > --- a/target-i386/cpu.h
> > +++ b/target-i386/cpu.h
> > @@ -1188,4 +1188,6 @@ void do_smm_enter(CPUX86State *env1);
> >  
> >  void cpu_report_tpr_access(CPUX86State *env, TPRAccess access);
> >  
> > +void enable_kvm_pv_eoi(void);
> > +
> >  #endif /* CPU_I386_H */


I'll fix the whitespace and repost.
Thanks for the review.

> 
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