[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [PATCH v4 15/17] xen: mapcache: Remove assumption of RAMBlock with 0 offset
On Tue, 30 Apr 2024, Edgar E. Iglesias wrote: > From: "Edgar E. Iglesias" <edgar.iglesias@xxxxxxx> > > The current mapcache assumes that all memory is mapped > in a single RAM MR (the first one with offset 0). Remove > this assumption and propagate the offset to the mapcache > so it can do reverse mappings (from hostptr -> ram_addr). > > This is in preparation for adding grant mappings. > > Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xxxxxxx> Looking at xen_remap_bucket, it is only using address_index (without adding ram_offset) to map foreign memory. From xen_remap_bucket, I would understand that address_index already includes the ram_offset. Meaning that if we want to map foreign mapping at address 0x5000, then address_index would be 0x5000, even if ram_offset is 0x1000. But then looking xen_ram_addr_from_mapcache_single ram_offset is added to paddr_index to calculate the physical address. So in that case we would want address_index to be 0x4000 and ram_offset to be 0x1000. But xen_remap_bucket would have to sum address_index and ram_offset to map foreign memory. So I am a bit confused, did I get it wrong? One more comment below. > --- > hw/xen/xen-mapcache.c | 25 ++++++++++++++++++------- > include/sysemu/xen-mapcache.h | 2 ++ > system/physmem.c | 8 ++++---- > 3 files changed, 24 insertions(+), 11 deletions(-) > > diff --git a/hw/xen/xen-mapcache.c b/hw/xen/xen-mapcache.c > index 09b5f36d9c..1b32d0c003 100644 > --- a/hw/xen/xen-mapcache.c > +++ b/hw/xen/xen-mapcache.c > @@ -43,6 +43,9 @@ typedef struct MapCacheEntry { > #define XEN_MAPCACHE_ENTRY_DUMMY (1 << 0) > uint8_t flags; > hwaddr size; > + > + /* Keep ram_addr offset for reverse mappings (hostptr -> ram_addr). */ > + ram_addr_t ram_offset; > struct MapCacheEntry *next; > } MapCacheEntry; > > @@ -165,7 +168,8 @@ static void xen_remap_bucket(MapCache *mc, > void *vaddr, > hwaddr size, > hwaddr address_index, > - bool dummy) > + bool dummy, > + ram_addr_t ram_offset) > { > uint8_t *vaddr_base; > xen_pfn_t *pfns; > @@ -244,6 +248,7 @@ static void xen_remap_bucket(MapCache *mc, > entry->size = size; > entry->valid_mapping = g_new0(unsigned long, > BITS_TO_LONGS(size >> XC_PAGE_SHIFT)); > + entry->ram_offset = ram_offset; > > if (dummy) { > entry->flags |= XEN_MAPCACHE_ENTRY_DUMMY; > @@ -264,6 +269,7 @@ static void xen_remap_bucket(MapCache *mc, > > static uint8_t *xen_map_cache_unlocked(MapCache *mc, > hwaddr phys_addr, hwaddr size, > + ram_addr_t ram_offset, > uint8_t lock, bool dma, bool is_write) > { > MapCacheEntry *entry, *pentry = NULL, > @@ -335,14 +341,16 @@ tryagain: > if (!entry) { > entry = g_new0(MapCacheEntry, 1); > pentry->next = entry; > - xen_remap_bucket(mc, entry, NULL, cache_size, address_index, dummy); > + xen_remap_bucket(mc, entry, NULL, cache_size, address_index, dummy, > + ram_offset); > } else if (!entry->lock) { > if (!entry->vaddr_base || entry->paddr_index != address_index || > entry->size != cache_size || > !test_bits(address_offset >> XC_PAGE_SHIFT, > test_bit_size >> XC_PAGE_SHIFT, > entry->valid_mapping)) { > - xen_remap_bucket(mc, entry, NULL, cache_size, address_index, > dummy); > + xen_remap_bucket(mc, entry, NULL, cache_size, address_index, > dummy, > + ram_offset); > } > } > > @@ -389,13 +397,15 @@ tryagain: > > uint8_t *xen_map_cache(MemoryRegion *mr, > hwaddr phys_addr, hwaddr size, > + ram_addr_t ram_addr_offset, > uint8_t lock, bool dma, > bool is_write) > { > uint8_t *p; > > mapcache_lock(mapcache); > - p = xen_map_cache_unlocked(mapcache, phys_addr, size, lock, dma, > is_write); > + p = xen_map_cache_unlocked(mapcache, phys_addr, size, ram_addr_offset, > + lock, dma, is_write); > mapcache_unlock(mapcache); > return p; > } > @@ -432,7 +442,8 @@ static ram_addr_t > xen_ram_addr_from_mapcache_single(MapCache *mc, void *ptr) > raddr = RAM_ADDR_INVALID; > } else { > raddr = (reventry->paddr_index << mc->bucket_shift) + > - ((unsigned long) ptr - (unsigned long) entry->vaddr_base); > + ((unsigned long) ptr - (unsigned long) entry->vaddr_base) + > + entry->ram_offset; > } > mapcache_unlock(mc); > return raddr; > @@ -627,8 +638,8 @@ static uint8_t *xen_replace_cache_entry_unlocked(MapCache > *mc, > > trace_xen_replace_cache_entry_dummy(old_phys_addr, new_phys_addr); > > - xen_remap_bucket(mapcache, entry, entry->vaddr_base, > - cache_size, address_index, false); > + xen_remap_bucket(mc, entry, entry->vaddr_base, > + cache_size, address_index, false, entry->ram_offset); > if (!test_bits(address_offset >> XC_PAGE_SHIFT, > test_bit_size >> XC_PAGE_SHIFT, > entry->valid_mapping)) { > diff --git a/include/sysemu/xen-mapcache.h b/include/sysemu/xen-mapcache.h > index 1ec9e66752..b5e3ea1bc0 100644 > --- a/include/sysemu/xen-mapcache.h > +++ b/include/sysemu/xen-mapcache.h > @@ -19,6 +19,7 @@ typedef hwaddr (*phys_offset_to_gaddr_t)(hwaddr phys_offset, > void xen_map_cache_init(phys_offset_to_gaddr_t f, > void *opaque); > uint8_t *xen_map_cache(MemoryRegion *mr, hwaddr phys_addr, hwaddr size, > + ram_addr_t ram_addr_offset, > uint8_t lock, bool dma, > bool is_write); > ram_addr_t xen_ram_addr_from_mapcache(void *ptr); > @@ -37,6 +38,7 @@ static inline void > xen_map_cache_init(phys_offset_to_gaddr_t f, > static inline uint8_t *xen_map_cache(MemoryRegion *mr, > hwaddr phys_addr, > hwaddr size, > + ram_addr_t ram_addr_offset, > uint8_t lock, > bool dma, > bool is_write) > diff --git a/system/physmem.c b/system/physmem.c > index 1a5ffcba2a..5b16eeccca 100644 > --- a/system/physmem.c > +++ b/system/physmem.c > @@ -2228,13 +2228,13 @@ static void *qemu_ram_ptr_length(RAMBlock *block, > ram_addr_t addr, > * In that case just map the requested area. > */ > if (xen_mr_is_memory(block->mr)) { > - return xen_map_cache(block->mr, addr, len, lock, lock, > - is_write); > + return xen_map_cache(block->mr, addr, len, block->offset, > + lock, lock, is_write); Have you considered not tracking offset and address separately and simply do this? return xen_map_cache(block->mr, addr + block->offset, len, lock, lock, is_write); > } > > block->host = xen_map_cache(block->mr, block->offset, > - block->max_length, 1, > - lock, is_write); > + block->max_length, 0, > + 1, lock, is_write); > } > > return ramblock_ptr(block, addr); > -- > 2.40.1 >
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |