From 19f703477314a5db09ffc3c0f6be9c45645f8302 Mon Sep 17 00:00:00 2001 From: Peter Maydell Date: Tue, 18 Feb 2020 11:24:57 +0000 Subject: Avoid address_space_rw() with a constant is_write argument MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The address_space_rw() function allows either reads or writes depending on the is_write argument passed to it; this is useful when the direction of the access is determined programmatically (as for instance when handling the KVM_EXIT_MMIO exit reason). Under the hood it just calls either address_space_write() or address_space_read_full(). We also use it a lot with a constant is_write argument, though, which has two issues: * when reading "address_space_rw(..., 1)" this is less immediately clear to the reader as being a write than "address_space_write(...)" * calling address_space_rw() bypasses the optimization in address_space_read() that fast-paths reads of a fixed length This commit was produced with the included Coccinelle script scripts/coccinelle/exec_rw_const.cocci. Signed-off-by: Peter Maydell Reviewed-by: Philippe Mathieu-Daudé Reviewed-by: Edgar E. Iglesias Reviewed-by: Laurent Vivier Reviewed-by: Cédric Le Goater Acked-by: Christian Borntraeger Reviewed-by: Cornelia Huck Reviewed-by: Alistair Francis Acked-by: David Gibson Message-Id: <20200218112457.22712-1-peter.maydell@linaro.org> [PMD: Update macvm_set_cr0() reported by Laurent Vivier] Signed-off-by: Philippe Mathieu-Daudé --- dma-helpers.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'dma-helpers.c') diff --git a/dma-helpers.c b/dma-helpers.c index d3871dc61e..e8a26e81e1 100644 --- a/dma-helpers.c +++ b/dma-helpers.c @@ -28,8 +28,8 @@ int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len) memset(fillbuf, c, FILLBUF_SIZE); while (len > 0) { l = len < FILLBUF_SIZE ? len : FILLBUF_SIZE; - error |= address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, - fillbuf, l, true); + error |= address_space_write(as, addr, MEMTXATTRS_UNSPECIFIED, + fillbuf, l); len -= l; addr += l; } -- cgit v1.2.3