From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41561) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X9M3L-0003Ad-Bj for qemu-devel@nongnu.org; Mon, 21 Jul 2014 18:27:33 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X9M3F-0002sg-22 for qemu-devel@nongnu.org; Mon, 21 Jul 2014 18:27:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:16322) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X9M3E-0002rT-PH for qemu-devel@nongnu.org; Mon, 21 Jul 2014 18:27:20 -0400 Date: Tue, 22 Jul 2014 00:29:47 +0300 From: "Michael S. Tsirkin" Message-ID: <20140721212947.GB5014@redhat.com> References: <1405955204-10438-1-git-send-email-pbonzini@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1405955204-10438-1-git-send-email-pbonzini@redhat.com> Subject: Re: [Qemu-devel] [PATCH for-2.1] exec: fix migration with devices that use address_space_rw List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: peter.maydell@linaro.org, quintela@redhat.com, qemu-devel@nongnu.org, dgilbert@redhat.com, kraxel@redhat.com On Mon, Jul 21, 2014 at 05:06:44PM +0200, Paolo Bonzini wrote: > Devices that use address_space_rw to write large areas to memory > (as opposed to address_space_map/unmap) were broken with respect > to migration since fe680d0 (exec: Limit translation limiting in > address_space_translate to xen, 2014-05-07). Such devices include > IDE CD-ROMs. > > The reason is that invalidate_and_set_dirty (called by address_space_rw > but not address_space_map/unmap) was only setting the dirty bit for > the first page in the translation. > > To fix this, introduce cpu_physical_memory_set_dirty_range_nocode that > is the same as cpu_physical_memory_set_dirty_range except it does not > muck with the DIRTY_MEMORY_CODE bitmap. This function can be used if > the caller invalidates translations with tb_invalidate_phys_page_range. > > There is another difference between cpu_physical_memory_set_dirty_range > and cpu_physical_memory_set_dirty_flag; the former includes a call > to xen_modified_memory. This is handled separately in > invalidate_and_set_dirty, and is not needed in other callers of > cpu_physical_memory_set_dirty_range_nocode, so leave it alone. > > Just one nit: now that invalidate_and_set_dirty takes care of handling > multiple pages, there is no need for address_space_unmap to wrap it > in a loop. In fact that loop would now be O(n^1). > > Reported-by: Dave Gilbert > Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin > --- > exec.c | 20 ++++---------------- > include/exec/ram_addr.h | 11 +++++++++++ > 2 files changed, 15 insertions(+), 16 deletions(-) > > diff --git a/exec.c b/exec.c > index 5a2a25e..765bd94 100644 > --- a/exec.c > +++ b/exec.c > @@ -1568,8 +1568,7 @@ static void notdirty_mem_write(void *opaque, hwaddr ram_addr, > default: > abort(); > } > - cpu_physical_memory_set_dirty_flag(ram_addr, DIRTY_MEMORY_MIGRATION); > - cpu_physical_memory_set_dirty_flag(ram_addr, DIRTY_MEMORY_VGA); > + cpu_physical_memory_set_dirty_range_nocode(ram_addr, size); > /* we remove the notdirty callback only if the code has been > flushed */ > if (!cpu_physical_memory_is_clean(ram_addr)) { > @@ -1978,8 +1977,7 @@ static void invalidate_and_set_dirty(hwaddr addr, > /* invalidate code */ > tb_invalidate_phys_page_range(addr, addr + length, 0); > /* set dirty bit */ > - cpu_physical_memory_set_dirty_flag(addr, DIRTY_MEMORY_VGA); > - cpu_physical_memory_set_dirty_flag(addr, DIRTY_MEMORY_MIGRATION); > + cpu_physical_memory_set_dirty_range_nocode(addr, length); > } > xen_modified_memory(addr, length); > } > @@ -2335,15 +2333,7 @@ void address_space_unmap(AddressSpace *as, void *buffer, hwaddr len, > mr = qemu_ram_addr_from_host(buffer, &addr1); > assert(mr != NULL); > if (is_write) { > - while (access_len) { > - unsigned l; > - l = TARGET_PAGE_SIZE; > - if (l > access_len) > - l = access_len; > - invalidate_and_set_dirty(addr1, l); > - addr1 += l; > - access_len -= l; > - } > + invalidate_and_set_dirty(addr1, access_len); > } > if (xen_enabled()) { > xen_invalidate_map_cache_entry(buffer); > @@ -2581,9 +2571,7 @@ void stl_phys_notdirty(AddressSpace *as, hwaddr addr, uint32_t val) > /* invalidate code */ > tb_invalidate_phys_page_range(addr1, addr1 + 4, 0); > /* set dirty bit */ > - cpu_physical_memory_set_dirty_flag(addr1, > - DIRTY_MEMORY_MIGRATION); > - cpu_physical_memory_set_dirty_flag(addr1, DIRTY_MEMORY_VGA); > + cpu_physical_memory_set_dirty_range_nocode(addr1, 4); > } > } > } > diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h > index e9eb831..6593be1 100644 > --- a/include/exec/ram_addr.h > +++ b/include/exec/ram_addr.h > @@ -71,6 +71,17 @@ static inline void cpu_physical_memory_set_dirty_flag(ram_addr_t addr, > set_bit(addr >> TARGET_PAGE_BITS, ram_list.dirty_memory[client]); > } > > +static inline void cpu_physical_memory_set_dirty_range_nocode(ram_addr_t start, > + ram_addr_t length) > +{ > + unsigned long end, page; > + > + end = TARGET_PAGE_ALIGN(start + length) >> TARGET_PAGE_BITS; > + page = start >> TARGET_PAGE_BITS; > + bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_MIGRATION], page, end - page); > + bitmap_set(ram_list.dirty_memory[DIRTY_MEMORY_VGA], page, end - page); > +} > + > static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start, > ram_addr_t length) > { > -- > 1.8.3.1