Re: [Xen-devel] [PATCH v3 01/14] xen/x86: Make mfn_to_gfn typesafe

[Julien Grall <julien.grall@arm.com>]

Hi,

@George can I get an ack for this patch?

Cheers,

On 6/3/19 5:03 PM, Julien Grall wrote:
> No functional changes intended.
> 
> Signed-off-by: Julien Grall <julien.grall@arm.com>
> 
> ---
>      Changes in v3:
>          - Remove gfn_x(...) for gfn used in parameter of __trace_var(...).
> 
>      Changes in v2:
>          - Patch added
> ---
>   xen/arch/x86/mm/p2m.c           |  2 +-
>   xen/arch/x86/mm/shadow/common.c | 31 ++++++++++++++++++-------------
>   xen/arch/x86/mm/shadow/multi.c  |  4 ++--
>   xen/include/asm-x86/p2m.h       |  6 +++---
>   4 files changed, 24 insertions(+), 19 deletions(-)
> 
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index 4c9954867c..279278715e 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -951,7 +951,7 @@ guest_physmap_add_entry(struct domain *d, gfn_t gfn, mfn_t mfn,
>           }
>           if ( page_get_owner(mfn_to_page(mfn_add(mfn, i))) != d )
>               continue;
> -        ogfn = _gfn(mfn_to_gfn(d, mfn_add(mfn, i)));
> +        ogfn = mfn_to_gfn(d, mfn_add(mfn, i));
>           if ( !gfn_eq(ogfn, _gfn(INVALID_M2P_ENTRY)) &&
>                !gfn_eq(ogfn, gfn_add(gfn, i)) )
>           {
> diff --git a/xen/arch/x86/mm/shadow/common.c b/xen/arch/x86/mm/shadow/common.c
> index 795201dc82..1e67bd072a 100644
> --- a/xen/arch/x86/mm/shadow/common.c
> +++ b/xen/arch/x86/mm/shadow/common.c
> @@ -474,7 +474,8 @@ static inline void trace_resync(int event, mfn_t gmfn)
>       if ( tb_init_done )
>       {
>           /* Convert gmfn to gfn */
> -        unsigned long gfn = mfn_to_gfn(current->domain, gmfn);
> +        gfn_t gfn = mfn_to_gfn(current->domain, gmfn);
> +
>           __trace_var(event, 0/*!tsc*/, sizeof(gfn), &gfn);
>       }
>   }
> @@ -985,7 +986,8 @@ static inline void trace_shadow_prealloc_unpin(struct domain *d, mfn_t smfn)
>       if ( tb_init_done )
>       {
>           /* Convert smfn to gfn */
> -        unsigned long gfn;
> +        gfn_t gfn;
> +
>           ASSERT(mfn_valid(smfn));
>           gfn = mfn_to_gfn(d, backpointer(mfn_to_page(smfn)));
>           __trace_var(TRC_SHADOW_PREALLOC_UNPIN, 0/*!tsc*/, sizeof(gfn), &gfn);
> @@ -1861,7 +1863,8 @@ static inline void trace_shadow_wrmap_bf(mfn_t gmfn)
>       if ( tb_init_done )
>       {
>           /* Convert gmfn to gfn */
> -        unsigned long gfn = mfn_to_gfn(current->domain, gmfn);
> +        gfn_t gfn = mfn_to_gfn(current->domain, gmfn);
> +
>           __trace_var(TRC_SHADOW_WRMAP_BF, 0/*!tsc*/, sizeof(gfn), &gfn);
>       }
>   }
> @@ -1946,7 +1949,7 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
>   #if SHADOW_OPTIMIZATIONS & SHOPT_WRITABLE_HEURISTIC
>       if ( curr->domain == d )
>       {
> -        unsigned long gfn;
> +        gfn_t gfn;
>           /* Heuristic: there is likely to be only one writeable mapping,
>            * and that mapping is likely to be in the current pagetable,
>            * in the guest's linear map (on non-HIGHPTE linux and windows)*/
> @@ -1969,8 +1972,9 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
>                   GUESS(0xC0000000UL + (fault_addr >> 10), 1);
>   
>               /* Linux lowmem: first 896MB is mapped 1-to-1 above 0xC0000000 */
> -            if ((gfn = mfn_to_gfn(d, gmfn)) < 0x38000 )
> -                GUESS(0xC0000000UL + (gfn << PAGE_SHIFT), 4);
> +            gfn = mfn_to_gfn(d, gmfn);
> +            if ( gfn_x(gfn) < 0x38000 )
> +                GUESS(0xC0000000UL + gfn_to_gaddr(gfn), 4);
>   
>               /* FreeBSD: Linear map at 0xBFC00000 */
>               if ( level == 1 )
> @@ -1987,8 +1991,9 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
>               }
>   
>               /* Linux lowmem: first 896MB is mapped 1-to-1 above 0xC0000000 */
> -            if ((gfn = mfn_to_gfn(d, gmfn)) < 0x38000 )
> -                GUESS(0xC0000000UL + (gfn << PAGE_SHIFT), 4);
> +            gfn = mfn_to_gfn(d, gmfn);
> +            if ( gfn_x(gfn) < 0x38000 )
> +                GUESS(0xC0000000UL + gfn_to_gaddr(gfn), 4);
>   
>               /* FreeBSD PAE: Linear map at 0xBF800000 */
>               switch ( level )
> @@ -2016,15 +2021,15 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
>                * had it at 0xffff810000000000, and older kernels yet had it
>                * at 0x0000010000000000UL */
>               gfn = mfn_to_gfn(d, gmfn);
> -            GUESS(0xffff880000000000UL + (gfn << PAGE_SHIFT), 4);
> -            GUESS(0xffff810000000000UL + (gfn << PAGE_SHIFT), 4);
> -            GUESS(0x0000010000000000UL + (gfn << PAGE_SHIFT), 4);
> +            GUESS(0xffff880000000000UL + gfn_to_gaddr(gfn), 4);
> +            GUESS(0xffff810000000000UL + gfn_to_gaddr(gfn), 4);
> +            GUESS(0x0000010000000000UL + gfn_to_gaddr(gfn), 4);
>   
>               /*
>                * 64bit Solaris kernel page map at
>                * kpm_vbase; 0xfffffe0000000000UL
>                */
> -            GUESS(0xfffffe0000000000UL + (gfn << PAGE_SHIFT), 4);
> +            GUESS(0xfffffe0000000000UL + gfn_to_gaddr(gfn), 4);
>   
>                /* FreeBSD 64bit: linear map 0xffff800000000000 */
>                switch ( level )
> @@ -2037,7 +2042,7 @@ int sh_remove_write_access(struct domain *d, mfn_t gmfn,
>                              + ((fault_addr & VADDR_MASK) >> 27), 6); break;
>                }
>                /* FreeBSD 64bit: direct map at 0xffffff0000000000 */
> -             GUESS(0xffffff0000000000 + (gfn << PAGE_SHIFT), 6);
> +             GUESS(0xffffff0000000000 + gfn_to_gaddr(gfn), 6);
>           }
>   
>   #undef GUESS
> diff --git a/xen/arch/x86/mm/shadow/multi.c b/xen/arch/x86/mm/shadow/multi.c
> index 5f8a745de2..74681ba85c 100644
> --- a/xen/arch/x86/mm/shadow/multi.c
> +++ b/xen/arch/x86/mm/shadow/multi.c
> @@ -1076,7 +1076,7 @@ static inline void shadow_vram_get_l1e(shadow_l1e_t new_sl1e,
>            || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
>           return;
>   
> -    gfn = mfn_to_gfn(d, mfn);
> +    gfn = gfn_x(mfn_to_gfn(d, mfn));
>       /* Page sharing not supported on shadow PTs */
>       BUG_ON(SHARED_M2P(gfn));
>   
> @@ -1107,7 +1107,7 @@ static inline void shadow_vram_put_l1e(shadow_l1e_t old_sl1e,
>            || !mfn_valid(mfn) )   /* mfn can be invalid in mmio_direct */
>           return;
>   
> -    gfn = mfn_to_gfn(d, mfn);
> +    gfn = gfn_x(mfn_to_gfn(d, mfn));
>       /* Page sharing not supported on shadow PTs */
>       BUG_ON(SHARED_M2P(gfn));
>   
> diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
> index 09ef7e02fd..1a075547e2 100644
> --- a/xen/include/asm-x86/p2m.h
> +++ b/xen/include/asm-x86/p2m.h
> @@ -506,12 +506,12 @@ static inline struct page_info *get_page_from_gfn(
>   }
>   
>   /* General conversion function from mfn to gfn */
> -static inline unsigned long mfn_to_gfn(const struct domain *d, mfn_t mfn)
> +static inline gfn_t mfn_to_gfn(const struct domain *d, mfn_t mfn)
>   {
>       if ( paging_mode_translate(d) )
> -        return get_gpfn_from_mfn(mfn_x(mfn));
> +        return _gfn(get_gpfn_from_mfn(mfn_x(mfn)));
>       else
> -        return mfn_x(mfn);
> +        return _gfn(mfn_x(mfn));
>   }
>   
>   #ifdef CONFIG_HVM
> 

-- 
Julien Grall

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