From 5d4c954931ba62661c6a1bc16ce604a012a10007 Mon Sep 17 00:00:00 2001 From: Anthony PERARD Date: Thu, 19 Dec 2019 15:43:22 +0000 Subject: Memory: Only call ramblock_ptr when needed in qemu_ram_writeback It is possible that a ramblock doesn't have memory that QEMU can access, this is the case with the Xen hypervisor. In order to avoid to trigger an assert, only call ramblock_ptr() when needed in qemu_ram_writeback(). This should fix migration of Xen guests that was broken with bd108a44bc29 ("migration: ram: Switch to ram block writeback"). Signed-off-by: Anthony PERARD Reviewed-by: Juan Quintela Acked-by: Paolo Bonzini Message-Id: <20191219154323.325255-1-anthony.perard@citrix.com> --- exec.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'exec.c') diff --git a/exec.c b/exec.c index 231d6e5641..0cc500d53a 100644 --- a/exec.c +++ b/exec.c @@ -2116,14 +2116,13 @@ int qemu_ram_resize(RAMBlock *block, ram_addr_t newsize, Error **errp) */ void qemu_ram_writeback(RAMBlock *block, ram_addr_t start, ram_addr_t length) { - void *addr = ramblock_ptr(block, start); - /* The requested range should fit in within the block range */ g_assert((start + length) <= block->used_length); #ifdef CONFIG_LIBPMEM /* The lack of support for pmem should not block the sync */ if (ramblock_is_pmem(block)) { + void *addr = ramblock_ptr(block, start); pmem_persist(addr, length); return; } @@ -2134,6 +2133,7 @@ void qemu_ram_writeback(RAMBlock *block, ram_addr_t start, ram_addr_t length) * specified as persistent (or is not one) - use the msync. * Less optimal but still achieves the same goal */ + void *addr = ramblock_ptr(block, start); if (qemu_msync(addr, length, block->fd)) { warn_report("%s: failed to sync memory range: start: " RAM_ADDR_FMT " length: " RAM_ADDR_FMT, -- cgit v1.2.3