From 712c2b41490a986a5dd99bec99b854bac4322201 Mon Sep 17 00:00:00 2001 From: Stefano Stabellini Date: Thu, 19 May 2011 18:35:46 +0100 Subject: [PATCH] xen: mapcache performance improvements Use qemu_invalidate_entry in cpu_physical_memory_unmap. Do not lock mapcache entries in qemu_get_ram_ptr if the address falls in the ramblock with offset == 0. We don't need to do that because the callers of qemu_get_ram_ptr either try to map an entire block, other from the main ramblock, or until the end of a page to implement a single read or write in the main ramblock. If we don't lock mapcache entries in qemu_get_ram_ptr we don't need to call qemu_invalidate_entry in qemu_put_ram_ptr anymore because we can leave with few long lived block mappings requested by devices. Also move the call to qemu_ram_addr_from_mapcache at the beginning of qemu_ram_addr_from_host. Signed-off-by: Stefano Stabellini Signed-off-by: Alexander Graf --- exec.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/exec.c b/exec.c index 238c173de4..7f14332c87 100644 --- a/exec.c +++ b/exec.c @@ -3085,9 +3085,10 @@ void *qemu_get_ram_ptr(ram_addr_t addr) if (xen_mapcache_enabled()) { /* We need to check if the requested address is in the RAM * because we don't want to map the entire memory in QEMU. + * In that case just map until the end of the page. */ if (block->offset == 0) { - return qemu_map_cache(addr, 0, 1); + return qemu_map_cache(addr, 0, 0); } else if (block->host == NULL) { block->host = qemu_map_cache(block->offset, block->length, 1); } @@ -3114,9 +3115,10 @@ void *qemu_safe_ram_ptr(ram_addr_t addr) if (xen_mapcache_enabled()) { /* We need to check if the requested address is in the RAM * because we don't want to map the entire memory in QEMU. + * In that case just map until the end of the page. */ if (block->offset == 0) { - return qemu_map_cache(addr, 0, 1); + return qemu_map_cache(addr, 0, 0); } else if (block->host == NULL) { block->host = qemu_map_cache(block->offset, block->length, 1); } @@ -3159,10 +3161,6 @@ void *qemu_ram_ptr_length(target_phys_addr_t addr, target_phys_addr_t *size) void qemu_put_ram_ptr(void *addr) { trace_qemu_put_ram_ptr(addr); - - if (xen_mapcache_enabled()) { - qemu_invalidate_entry(block->host); - } } int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr) @@ -3170,6 +3168,11 @@ int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr) RAMBlock *block; uint8_t *host = ptr; + if (xen_mapcache_enabled()) { + *ram_addr = qemu_ram_addr_from_mapcache(ptr); + return 0; + } + QLIST_FOREACH(block, &ram_list.blocks, next) { /* This case append when the block is not mapped. */ if (block->host == NULL) { @@ -3181,11 +3184,6 @@ int qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr) } } - if (xen_mapcache_enabled()) { - *ram_addr = qemu_ram_addr_from_mapcache(ptr); - return 0; - } - return -1; } @@ -4086,13 +4084,7 @@ void cpu_physical_memory_unmap(void *buffer, target_phys_addr_t len, } } if (xen_mapcache_enabled()) { - uint8_t *buffer1 = buffer; - uint8_t *end_buffer = buffer + len; - - while (buffer1 < end_buffer) { - qemu_put_ram_ptr(buffer1); - buffer1 += TARGET_PAGE_SIZE; - } + qemu_invalidate_entry(buffer); } return; }