From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:59457) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gxD0X-0007jU-OU for qemu-devel@nongnu.org; Fri, 22 Feb 2019 10:45:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gxD0W-0003rp-Nn for qemu-devel@nongnu.org; Fri, 22 Feb 2019 10:45:01 -0500 Received: from mail-wm1-x342.google.com ([2a00:1450:4864:20::342]:51189) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gxD0W-0003pp-F6 for qemu-devel@nongnu.org; Fri, 22 Feb 2019 10:45:00 -0500 Received: by mail-wm1-x342.google.com with SMTP id x7so2380124wmj.0 for ; Fri, 22 Feb 2019 07:45:00 -0800 (PST) From: =?UTF-8?q?Alex=20Benn=C3=A9e?= Date: Fri, 22 Feb 2019 15:44:54 +0000 Message-Id: <20190222154454.30289-1-alex.bennee@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH v4] hw/block: better reporting on pflash backing file mismatch List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: lersek@redhat.com, armbru@redhat.com, stappers@stappers.nl, =?UTF-8?q?Alex=20Benn=C3=A9e?= It looks like there was going to be code to check we had some sort of alignment so lets replace it with an actual check. This is a bit more useful than the enigmatic "failed to read the initial flash content" when we attempt to read the number of bytes the device should have. This is a potential confusing stumbling block when you move from using -bios to using -drive if=pflash,file=blob,format=raw,readonly for loading your firmware code. To mitigate that we automatically pad in the read-only case and warn the user when we have performed magic to enable things to Just Work (tm). Signed-off-by: Alex Bennée --- v3 - tweak commit title/commentary - use total_len instead of device_len for checks - if the device is read-only do the padding for them - accept baking_len > total_len (how to warn_report with NULL *errp?) v4 - error check blk_getlength - optimise memset and use NOR erase pattern - restore singular device (overly confusing) - add warn_report for when we do magic --- hw/block/pflash_cfi01.c | 40 +++++++++++++++++++++++++++++++++------- 1 file changed, 33 insertions(+), 7 deletions(-) diff --git a/hw/block/pflash_cfi01.c b/hw/block/pflash_cfi01.c index 00c2efd0d7..c69ecc20a0 100644 --- a/hw/block/pflash_cfi01.c +++ b/hw/block/pflash_cfi01.c @@ -45,6 +45,7 @@ #include "qemu/bitops.h" #include "qemu/host-utils.h" #include "qemu/log.h" +#include "qemu/error-report.h" #include "hw/sysbus.h" #include "sysemu/sysemu.h" #include "trace.h" @@ -714,13 +715,6 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp) } device_len = sector_len_per_device * blocks_per_device; - /* XXX: to be fixed */ -#if 0 - if (total_len != (8 * 1024 * 1024) && total_len != (16 * 1024 * 1024) && - total_len != (32 * 1024 * 1024) && total_len != (64 * 1024 * 1024)) - return NULL; -#endif - memory_region_init_rom_device( &pfl->mem, OBJECT(dev), &pflash_cfi01_ops, @@ -747,6 +741,38 @@ static void pflash_cfi01_realize(DeviceState *dev, Error **errp) } if (pfl->blk) { + /* + * Validate the backing store is the right size for pflash + * devices. It should be padded to a multiple of the flash + * block size. If the device is read-only we can elide the + * check and just null pad the region first. If the user + * supplies a larger file we ignore the tail. + */ + int64_t backing_len = blk_getlength(pfl->blk); + if (backing_len < 0) { + error_setg(errp, "unable to check size of backing file"); + return; + } + + if (backing_len < total_len) { + if (pfl->ro) { + size_t pad_bytes = total_len - backing_len; + /* pad with NOR erase pattern */ + memset((uint8_t*)pfl->storage + backing_len, 0xff, pad_bytes); + warn_report("device needs %" PRIu64 + " bytes, padded with %zd 0xff bytes", + total_len, pad_bytes); + total_len = backing_len; + } else { + error_setg(errp, "device needs %" PRIu64 " bytes, " + "backing file provides only %" PRIu64 " bytes", + total_len, backing_len); + return; + } + } else if (backing_len > total_len) { + warn_report("device needs %" PRIu64 " bytes, rest ignored", total_len); + } + /* read the initial flash content */ ret = blk_pread(pfl->blk, 0, pfl->storage, total_len); -- 2.20.1