From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= Date: Sat, 4 May 2019 07:59:35 -0600 Subject: qxl: fix -Waddress-of-packed-member MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The GCC9 compiler complains about QXL code that takes the address of members of the 'struct QXLReleaseRing' which is marked packed: CC hw/display/qxl.o /home/elmarco/src/qemu/hw/display/qxl.c: In function 'init_qxl_ram': /home/elmarco/src/qemu/hw/display/qxl.c:50:19: warning: taking address of packed member of 'struct QXLReleaseRing_ring_el' may result in an unaligned pointer value [-Waddress-of-packed-member] 50 | ret = &(r)->items[prod].el; \ | ^~~~~~~~~~~~~~~~~~~~ /home/elmarco/src/qemu/hw/display/qxl.c:429:5: note: in expansion of macro 'SPICE_RING_PROD_ITEM' 429 | SPICE_RING_PROD_ITEM(d, &d->ram->release_ring, item); | ^~~~~~~~~~~~~~~~~~~~ /home/elmarco/src/qemu/hw/display/qxl.c: In function 'qxl_push_free_res': /home/elmarco/src/qemu/hw/display/qxl.c:50:19: warning: taking address of packed member of 'struct QXLReleaseRing_ring_el' may result in an unaligned pointer value [-Waddress-of-packed-member] 50 | ret = &(r)->items[prod].el; \ | ^~~~~~~~~~~~~~~~~~~~ /home/elmarco/src/qemu/hw/display/qxl.c:762:5: note: in expansion of macro 'SPICE_RING_PROD_ITEM' 762 | SPICE_RING_PROD_ITEM(d, ring, item); | ^~~~~~~~~~~~~~~~~~~~ /home/elmarco/src/qemu/hw/display/qxl.c: In function 'interface_release_resource': /home/elmarco/src/qemu/hw/display/qxl.c:50:19: warning: taking address of packed member of 'struct QXLReleaseRing_ring_el' may result in an unaligned pointer value [-Waddress-of-packed-member] 50 | ret = &(r)->items[prod].el; \ | ^~~~~~~~~~~~~~~~~~~~ /home/elmarco/src/qemu/hw/display/qxl.c:795:5: note: in expansion of macro 'SPICE_RING_PROD_ITEM' 795 | SPICE_RING_PROD_ITEM(qxl, ring, item); | ^~~~~~~~~~~~~~~~~~~~ Replace pointer usage by direct structure/array access instead. Signed-off-by: Marc-André Lureau Signed-off-by: Bruce Rogers --- hw/display/qxl.c | 83 +++++++++++++++++++++++++++++------------------- 1 file changed, 50 insertions(+), 33 deletions(-) diff --git a/hw/display/qxl.c b/hw/display/qxl.c index c8ce5781e0..12d83dd6f1 100644 --- a/hw/display/qxl.c +++ b/hw/display/qxl.c @@ -39,29 +39,49 @@ * abort we just qxl_set_guest_bug and set the return to NULL. Still * it may happen as a result of emulator bug as well. */ -#undef SPICE_RING_PROD_ITEM -#define SPICE_RING_PROD_ITEM(qxl, r, ret) { \ - uint32_t prod = (r)->prod & SPICE_RING_INDEX_MASK(r); \ - if (prod >= ARRAY_SIZE((r)->items)) { \ - qxl_set_guest_bug(qxl, "SPICE_RING_PROD_ITEM indices mismatch " \ - "%u >= %zu", prod, ARRAY_SIZE((r)->items)); \ - ret = NULL; \ - } else { \ - ret = &(r)->items[prod].el; \ - } \ +#define SPICE_RING_GET_CHECK(qxl, r, field) ({ \ + field = (r)->field & SPICE_RING_INDEX_MASK(r); \ + bool mismatch = field >= ARRAY_SIZE((r)->items); \ + if (mismatch) { \ + qxl_set_guest_bug(qxl, "SPICE_RING_GET %s indices mismatch " \ + "%u >= %zu", stringify(field), field, \ + ARRAY_SIZE((r)->items)); \ + } \ + !mismatch; \ +}) + +static inline uint64_t +qxl_release_ring_get_prod(PCIQXLDevice *qxl) +{ + struct QXLReleaseRing *ring = &qxl->ram->release_ring; + uint32_t prod; + bool ok = SPICE_RING_GET_CHECK(qxl, ring, prod); + assert(ok); + + return ring->items[prod].el; +} + +static inline bool +qxl_release_ring_set_prod(PCIQXLDevice *qxl, uint64_t val) +{ + struct QXLReleaseRing *ring = &qxl->ram->release_ring; + uint32_t prod; + bool ok = SPICE_RING_GET_CHECK(qxl, ring, prod); + if (ok) { + ring->items[prod].el = val; } + return ok; +} #undef SPICE_RING_CONS_ITEM -#define SPICE_RING_CONS_ITEM(qxl, r, ret) { \ - uint32_t cons = (r)->cons & SPICE_RING_INDEX_MASK(r); \ - if (cons >= ARRAY_SIZE((r)->items)) { \ - qxl_set_guest_bug(qxl, "SPICE_RING_CONS_ITEM indices mismatch " \ - "%u >= %zu", cons, ARRAY_SIZE((r)->items)); \ - ret = NULL; \ - } else { \ - ret = &(r)->items[cons].el; \ - } \ - } +#define SPICE_RING_CONS_ITEM(qxl, r, ret) { \ + uint32_t cons; \ + if (!SPICE_RING_GET_CHECK(qxl, r, cons)) { \ + ret = NULL; \ + } else { \ + ret = &(r)->items[cons].el; \ + } \ +} #undef ALIGN #define ALIGN(a, b) (((a) + ((b) - 1)) & ~((b) - 1)) @@ -414,7 +434,6 @@ static void init_qxl_rom(PCIQXLDevice *d) static void init_qxl_ram(PCIQXLDevice *d) { uint8_t *buf; - uint64_t *item; buf = d->vga.vram_ptr; d->ram = (QXLRam *)(buf + le32_to_cpu(d->shadow_rom.ram_header_offset)); @@ -426,9 +445,9 @@ static void init_qxl_ram(PCIQXLDevice *d) SPICE_RING_INIT(&d->ram->cmd_ring); SPICE_RING_INIT(&d->ram->cursor_ring); SPICE_RING_INIT(&d->ram->release_ring); - SPICE_RING_PROD_ITEM(d, &d->ram->release_ring, item); - assert(item); - *item = 0; + if (!qxl_release_ring_set_prod(d, 0)) { + g_assert_not_reached(); + } qxl_ring_set_dirty(d); } @@ -732,7 +751,6 @@ static int interface_req_cmd_notification(QXLInstance *sin) static inline void qxl_push_free_res(PCIQXLDevice *d, int flush) { QXLReleaseRing *ring = &d->ram->release_ring; - uint64_t *item; int notify; #define QXL_FREE_BUNCH_SIZE 32 @@ -759,11 +777,9 @@ static inline void qxl_push_free_res(PCIQXLDevice *d, int flush) if (notify) { qxl_send_events(d, QXL_INTERRUPT_DISPLAY); } - SPICE_RING_PROD_ITEM(d, ring, item); - if (!item) { + if (!qxl_release_ring_set_prod(d, 0)) { return; } - *item = 0; d->num_free_res = 0; d->last_release = NULL; qxl_ring_set_dirty(d); @@ -775,7 +791,8 @@ static void interface_release_resource(QXLInstance *sin, { PCIQXLDevice *qxl = container_of(sin, PCIQXLDevice, ssd.qxl); QXLReleaseRing *ring; - uint64_t *item, id; + uint32_t prod; + uint64_t id; if (ext.group_id == MEMSLOT_GROUP_HOST) { /* host group -> vga mode update request */ @@ -792,16 +809,16 @@ static void interface_release_resource(QXLInstance *sin, * pci bar 0, $command.release_info */ ring = &qxl->ram->release_ring; - SPICE_RING_PROD_ITEM(qxl, ring, item); - if (!item) { + + if (!SPICE_RING_GET_CHECK(qxl, ring, prod)) { return; } - if (*item == 0) { + if (qxl_release_ring_get_prod(qxl) == 0) { /* stick head into the ring */ id = ext.info->id; ext.info->next = 0; qxl_ram_set_dirty(qxl, &ext.info->next); - *item = id; + qxl_release_ring_set_prod(qxl, id); qxl_ring_set_dirty(qxl); } else { /* append item to the list */