On 10/12/2015 00:12, Andy Lutomirski wrote:
> Signed-off-by: Andy Lutomirski <l...@kernel.org>
> ---
>  arch/x86/entry/vdso/vclock_gettime.c  | 20 ++++++++------------
>  arch/x86/entry/vdso/vdso-layout.lds.S |  3 ++-
>  arch/x86/entry/vdso/vdso2c.c          |  3 +++
>  arch/x86/entry/vdso/vma.c             | 13 +++++++++++++
>  arch/x86/include/asm/pvclock.h        |  9 +++++++++
>  arch/x86/include/asm/vdso.h           |  1 +
>  arch/x86/kernel/kvmclock.c            |  5 +++++
>  7 files changed, 41 insertions(+), 13 deletions(-)
> 
> diff --git a/arch/x86/entry/vdso/vclock_gettime.c 
> b/arch/x86/entry/vdso/vclock_gettime.c
> index c325ba1bdddf..5dd363d54348 100644
> --- a/arch/x86/entry/vdso/vclock_gettime.c
> +++ b/arch/x86/entry/vdso/vclock_gettime.c
> @@ -36,6 +36,11 @@ static notrace cycle_t vread_hpet(void)
>  }
>  #endif
>  
> +#ifdef CONFIG_PARAVIRT_CLOCK
> +extern u8 pvclock_page
> +     __attribute__((visibility("hidden")));
> +#endif
> +
>  #ifndef BUILD_VDSO32
>  
>  #include <linux/kernel.h>
> @@ -62,23 +67,14 @@ notrace static long vdso_fallback_gtod(struct timeval 
> *tv, struct timezone *tz)
>  
>  #ifdef CONFIG_PARAVIRT_CLOCK
>  
> -static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
> +static notrace const struct pvclock_vsyscall_time_info *get_pvti0(void)
>  {
> -     const struct pvclock_vsyscall_time_info *pvti_base;
> -     int idx = cpu / (PAGE_SIZE/PVTI_SIZE);
> -     int offset = cpu % (PAGE_SIZE/PVTI_SIZE);
> -
> -     BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END);
> -
> -     pvti_base = (struct pvclock_vsyscall_time_info *)
> -                 __fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx);
> -
> -     return &pvti_base[offset];
> +     return (const struct pvclock_vsyscall_time_info *)&pvclock_page;
>  }
>  
>  static notrace cycle_t vread_pvclock(int *mode)
>  {
> -     const struct pvclock_vcpu_time_info *pvti = &get_pvti(0)->pvti;
> +     const struct pvclock_vcpu_time_info *pvti = &get_pvti0()->pvti;
>       cycle_t ret;
>       u64 tsc, pvti_tsc;
>       u64 last, delta, pvti_system_time;
> diff --git a/arch/x86/entry/vdso/vdso-layout.lds.S 
> b/arch/x86/entry/vdso/vdso-layout.lds.S
> index de2c921025f5..4158acc17df0 100644
> --- a/arch/x86/entry/vdso/vdso-layout.lds.S
> +++ b/arch/x86/entry/vdso/vdso-layout.lds.S
> @@ -25,7 +25,7 @@ SECTIONS
>        * segment.
>        */
>  
> -     vvar_start = . - 2 * PAGE_SIZE;
> +     vvar_start = . - 3 * PAGE_SIZE;
>       vvar_page = vvar_start;
>  
>       /* Place all vvars at the offsets in asm/vvar.h. */
> @@ -36,6 +36,7 @@ SECTIONS
>  #undef EMIT_VVAR
>  
>       hpet_page = vvar_start + PAGE_SIZE;
> +     pvclock_page = vvar_start + 2 * PAGE_SIZE;
>  
>       . = SIZEOF_HEADERS;
>  
> diff --git a/arch/x86/entry/vdso/vdso2c.c b/arch/x86/entry/vdso/vdso2c.c
> index 785d9922b106..491020b2826d 100644
> --- a/arch/x86/entry/vdso/vdso2c.c
> +++ b/arch/x86/entry/vdso/vdso2c.c
> @@ -73,6 +73,7 @@ enum {
>       sym_vvar_start,
>       sym_vvar_page,
>       sym_hpet_page,
> +     sym_pvclock_page,
>       sym_VDSO_FAKE_SECTION_TABLE_START,
>       sym_VDSO_FAKE_SECTION_TABLE_END,
>  };
> @@ -80,6 +81,7 @@ enum {
>  const int special_pages[] = {
>       sym_vvar_page,
>       sym_hpet_page,
> +     sym_pvclock_page,
>  };
>  
>  struct vdso_sym {
> @@ -91,6 +93,7 @@ struct vdso_sym required_syms[] = {
>       [sym_vvar_start] = {"vvar_start", true},
>       [sym_vvar_page] = {"vvar_page", true},
>       [sym_hpet_page] = {"hpet_page", true},
> +     [sym_pvclock_page] = {"pvclock_page", true},
>       [sym_VDSO_FAKE_SECTION_TABLE_START] = {
>               "VDSO_FAKE_SECTION_TABLE_START", false
>       },
> diff --git a/arch/x86/entry/vdso/vma.c b/arch/x86/entry/vdso/vma.c
> index 64df47148160..aa828191c654 100644
> --- a/arch/x86/entry/vdso/vma.c
> +++ b/arch/x86/entry/vdso/vma.c
> @@ -100,6 +100,7 @@ static int map_vdso(const struct vdso_image *image, bool 
> calculate_addr)
>               .name = "[vvar]",
>               .pages = no_pages,
>       };
> +     struct pvclock_vsyscall_time_info *pvti;
>  
>       if (calculate_addr) {
>               addr = vdso_addr(current->mm->start_stack,
> @@ -169,6 +170,18 @@ static int map_vdso(const struct vdso_image *image, bool 
> calculate_addr)
>       }
>  #endif
>  
> +     pvti = pvclock_pvti_cpu0_va();
> +     if (pvti && image->sym_pvclock_page) {
> +             ret = remap_pfn_range(vma,
> +                                   text_start + image->sym_pvclock_page,
> +                                   __pa(pvti) >> PAGE_SHIFT,
> +                                   PAGE_SIZE,
> +                                   PAGE_READONLY);
> +
> +             if (ret)
> +                     goto up_fail;
> +     }
> +
>  up_fail:
>       if (ret)
>               current->mm->context.vdso = NULL;
> diff --git a/arch/x86/include/asm/pvclock.h b/arch/x86/include/asm/pvclock.h
> index 7a6bed5c08bc..3864398c7cb2 100644
> --- a/arch/x86/include/asm/pvclock.h
> +++ b/arch/x86/include/asm/pvclock.h
> @@ -4,6 +4,15 @@
>  #include <linux/clocksource.h>
>  #include <asm/pvclock-abi.h>
>  
> +#ifdef CONFIG_PARAVIRT_CLOCK
> +extern struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void);
> +#else
> +static inline struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
> +{
> +     return NULL;
> +}
> +#endif
> +
>  /* some helper functions for xen and kvm pv clock sources */
>  cycle_t pvclock_clocksource_read(struct pvclock_vcpu_time_info *src);
>  u8 pvclock_read_flags(struct pvclock_vcpu_time_info *src);
> diff --git a/arch/x86/include/asm/vdso.h b/arch/x86/include/asm/vdso.h
> index 756de9190aec..deabaf9759b6 100644
> --- a/arch/x86/include/asm/vdso.h
> +++ b/arch/x86/include/asm/vdso.h
> @@ -22,6 +22,7 @@ struct vdso_image {
>  
>       long sym_vvar_page;
>       long sym_hpet_page;
> +     long sym_pvclock_page;
>       long sym_VDSO32_NOTE_MASK;
>       long sym___kernel_sigreturn;
>       long sym___kernel_rt_sigreturn;
> diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> index 2bd81e302427..ec1b06dc82d2 100644
> --- a/arch/x86/kernel/kvmclock.c
> +++ b/arch/x86/kernel/kvmclock.c
> @@ -45,6 +45,11 @@ early_param("no-kvmclock", parse_no_kvmclock);
>  static struct pvclock_vsyscall_time_info *hv_clock;
>  static struct pvclock_wall_clock wall_clock;
>  
> +struct pvclock_vsyscall_time_info *pvclock_pvti_cpu0_va(void)
> +{
> +     return hv_clock;
> +}
> +
>  /*
>   * The wallclock is the time of day when we booted. Since then, some time may
>   * have elapsed since the hypervisor wrote the data. So we try to account for
> 

Acked-by: Paolo Bonzini <pbonz...@redhat.com>
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