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Re: [Qemu-devel] [PATCH] exec: revert MemoryRegionCache
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH] exec: revert MemoryRegionCache |
Date: |
Mon, 3 Apr 2017 19:15:35 +0300 |
On Mon, Apr 03, 2017 at 03:39:01PM +0200, Paolo Bonzini wrote:
> MemoryRegionCache did not know about virtio support for IOMMUs (because the
> two features were developed at the same time). Revert MemoryRegionCache
> to "normal" address_space_* operations for 2.9, as it is simpler than
> undoing the virtio patches.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
Reviewed-by: Michael S. Tsirkin <address@hidden>
who's merging this? Me?
> ---
> exec.c | 64
> +++++++++------------------------------------------
> include/exec/memory.h | 10 ++++----
> 2 files changed, 15 insertions(+), 59 deletions(-)
>
> diff --git a/exec.c b/exec.c
> index e57a8a2..c97ef4a 100644
> --- a/exec.c
> +++ b/exec.c
> @@ -3236,75 +3236,33 @@ int64_t address_space_cache_init(MemoryRegionCache
> *cache,
> hwaddr len,
> bool is_write)
> {
> - hwaddr l, xlat;
> - MemoryRegion *mr;
> - void *ptr;
> -
> - assert(len > 0);
> -
> - l = len;
> - mr = address_space_translate(as, addr, &xlat, &l, is_write);
> - if (!memory_access_is_direct(mr, is_write)) {
> - return -EINVAL;
> - }
> -
> - l = address_space_extend_translation(as, addr, len, mr, xlat, l,
> is_write);
> - ptr = qemu_ram_ptr_length(mr->ram_block, xlat, &l);
> -
> - cache->xlat = xlat;
> - cache->is_write = is_write;
> - cache->mr = mr;
> - cache->ptr = ptr;
> - cache->len = l;
> - memory_region_ref(cache->mr);
> -
> - return l;
> + cache->len = len;
> + cache->as = as;
> + cache->xlat = addr;
> + return len;
> }
>
> void address_space_cache_invalidate(MemoryRegionCache *cache,
> hwaddr addr,
> hwaddr access_len)
> {
> - assert(cache->is_write);
> - invalidate_and_set_dirty(cache->mr, addr + cache->xlat, access_len);
> }
>
> void address_space_cache_destroy(MemoryRegionCache *cache)
> {
> - if (!cache->mr) {
> - return;
> - }
> -
> - if (xen_enabled()) {
> - xen_invalidate_map_cache_entry(cache->ptr);
> - }
> - memory_region_unref(cache->mr);
> - cache->mr = NULL;
> -}
> -
> -/* Called from RCU critical section. This function has the same
> - * semantics as address_space_translate, but it only works on a
> - * predefined range of a MemoryRegion that was mapped with
> - * address_space_cache_init.
> - */
> -static inline MemoryRegion *address_space_translate_cached(
> - MemoryRegionCache *cache, hwaddr addr, hwaddr *xlat,
> - hwaddr *plen, bool is_write)
> -{
> - assert(addr < cache->len && *plen <= cache->len - addr);
> - *xlat = addr + cache->xlat;
> - return cache->mr;
> + cache->as = NULL;
> }
>
> #define ARG1_DECL MemoryRegionCache *cache
> #define ARG1 cache
> #define SUFFIX _cached
> -#define TRANSLATE(...) address_space_translate_cached(cache,
> __VA_ARGS__)
> +#define TRANSLATE(addr, ...) \
> + address_space_translate(cache->as, cache->xlat + (addr), __VA_ARGS__)
> #define IS_DIRECT(mr, is_write) true
> -#define MAP_RAM(mr, ofs) (cache->ptr + (ofs - cache->xlat))
> -#define INVALIDATE(mr, ofs, len) ((void)0)
> -#define RCU_READ_LOCK() ((void)0)
> -#define RCU_READ_UNLOCK() ((void)0)
> +#define MAP_RAM(mr, ofs) qemu_map_ram_ptr((mr)->ram_block, ofs)
> +#define INVALIDATE(mr, ofs, len) invalidate_and_set_dirty(mr, ofs, len)
> +#define RCU_READ_LOCK() rcu_read_lock()
> +#define RCU_READ_UNLOCK() rcu_read_unlock()
> #include "memory_ldst.inc.c"
>
> /* virtual memory access for debug (includes writing to ROM) */
> diff --git a/include/exec/memory.h b/include/exec/memory.h
> index e39256a..f20b191 100644
> --- a/include/exec/memory.h
> +++ b/include/exec/memory.h
> @@ -1426,13 +1426,11 @@ void stq_be_phys(AddressSpace *as, hwaddr addr,
> uint64_t val);
>
> struct MemoryRegionCache {
> hwaddr xlat;
> - void *ptr;
> hwaddr len;
> - MemoryRegion *mr;
> - bool is_write;
> + AddressSpace *as;
> };
>
> -#define MEMORY_REGION_CACHE_INVALID ((MemoryRegionCache) { .mr = NULL })
> +#define MEMORY_REGION_CACHE_INVALID ((MemoryRegionCache) { .as = NULL })
>
> /* address_space_cache_init: prepare for repeated access to a physical
> * memory region
> @@ -1688,7 +1686,7 @@ address_space_read_cached(MemoryRegionCache *cache,
> hwaddr addr,
> void *buf, int len)
> {
> assert(addr < cache->len && len <= cache->len - addr);
> - memcpy(buf, cache->ptr + addr, len);
> + address_space_read(cache->as, cache->xlat + addr,
> MEMTXATTRS_UNSPECIFIED, buf, len);
> }
>
> /**
> @@ -1704,7 +1702,7 @@ address_space_write_cached(MemoryRegionCache *cache,
> hwaddr addr,
> void *buf, int len)
> {
> assert(addr < cache->len && len <= cache->len - addr);
> - memcpy(cache->ptr + addr, buf, len);
> + address_space_write(cache->as, cache->xlat + addr,
> MEMTXATTRS_UNSPECIFIED, buf, len);
> }
>
> #endif
> --
> 2.9.3