| Message ID | c9bbe8373c91444bbc2f2fd2c7a5059a2cf7c552.1374687002.git.jcody@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Wed, 07/24 13:54, Jeff Cody wrote: > This adds the ability to update the headers in a VHDX image, including > generating a new MS-compatible GUID. > > As VHDX depends on uuid.h, VHDX is now a configurable build option. If > VHDX support is enabled, that will also enable uuid as well. The > default is to have VHDX enabled. > > To enable/disable VHDX: --enable-vhdx, --disable-vhdx > > Signed-off-by: Jeff Cody <jcody@redhat.com> > --- > block/Makefile.objs | 2 +- > block/vhdx.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++- > block/vhdx.h | 12 +++- > configure | 13 +++++ > 4 files changed, 180 insertions(+), 4 deletions(-) > > diff --git a/block/Makefile.objs b/block/Makefile.objs > index 4cf9aa4..e5e54e6 100644 > --- a/block/Makefile.objs > +++ b/block/Makefile.objs > @@ -2,7 +2,7 @@ block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat > block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o > block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o > block-obj-y += qed-check.o > -block-obj-y += vhdx.o > +block-obj-$(CONFIG_VHDX) += vhdx.o > block-obj-y += parallels.o blkdebug.o blkverify.o > block-obj-y += snapshot.o qapi.o > block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o > diff --git a/block/vhdx.c b/block/vhdx.c > index 56bc88e..13e486d 100644 > --- a/block/vhdx.c > +++ b/block/vhdx.c > @@ -21,6 +21,7 @@ > #include "qemu/crc32c.h" > #include "block/vhdx.h" > > +#include <uuid/uuid.h> > > /* Several metadata and region table data entries are identified by > * guids in a MS-specific GUID format. */ > @@ -156,11 +157,40 @@ typedef struct BDRVVHDXState { > VHDXBatEntry *bat; > uint64_t bat_offset; > > + MSGUID session_guid; > + > + > VHDXParentLocatorHeader parent_header; > VHDXParentLocatorEntry *parent_entries; > > } BDRVVHDXState; > > +/* Calculates new checksum. > + * > + * Zero is substituted during crc calculation for the original crc field > + * crc_offset: byte offset in buf of the buffer crc > + * buf: buffer pointer > + * size: size of buffer (must be > crc_offset+4) > + * > + * Note: The resulting checksum is in the CPU endianness, not necessarily > + * in the file format endianness (LE). Any header export to disk should > + * make sure that vhdx_header_le_export() is used to convert to the > + * correct endianness > + */ > +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset) > +{ > + uint32_t crc; > + > + assert(buf != NULL); > + assert(size > (crc_offset + 4)); > + > + memset(buf + crc_offset, 0, sizeof(crc)); > + crc = crc32c(0xffffffff, buf, size); > + memcpy(buf + crc_offset, &crc, sizeof(crc)); > + > + return crc; > +} > + > uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, > int crc_offset) > { > @@ -212,6 +242,24 @@ bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset) > > > /* > + * This generates a UUID that is compliant with the MS GUIDs used > + * in the VHDX spec (and elsewhere). > + * > + * We can do this with uuid_generate if uuid.h is present, > + * however not all systems have uuid and the generation is > + * pretty straightforward for the DCE + random usage case > + * > + */ > +void vhdx_guid_generate(MSGUID *guid) > +{ > + uuid_t uuid; > + assert(guid != NULL); > + > + uuid_generate(uuid); > + memcpy(guid, uuid, 16); > +} > + > +/* > * Per the MS VHDX Specification, for every VHDX file: > * - The header section is fixed size - 1 MB > * - The header section is always the first "object" > @@ -249,6 +297,107 @@ static void vhdx_header_le_import(VHDXHeader *h) > le64_to_cpus(&h->log_offset); > } > > +/* All VHDX structures on disk are little endian */ > +static void vhdx_header_le_export(VHDXHeader *orig_h, VHDXHeader *new_h) > +{ > + assert(orig_h != NULL); > + assert(new_h != NULL); > + > + new_h->signature = cpu_to_le32(orig_h->signature); > + new_h->checksum = cpu_to_le32(orig_h->checksum); > + new_h->sequence_number = cpu_to_le64(orig_h->sequence_number); > + > + memcpy(&new_h->file_write_guid, &orig_h->file_write_guid, sizeof(MSGUID)); > + memcpy(&new_h->data_write_guid, &orig_h->data_write_guid, sizeof(MSGUID)); > + memcpy(&new_h->log_guid, &orig_h->log_guid, sizeof(MSGUID)); > + > + cpu_to_leguids(&new_h->file_write_guid); > + cpu_to_leguids(&new_h->data_write_guid); > + cpu_to_leguids(&new_h->log_guid); > + > + new_h->log_version = cpu_to_le16(orig_h->log_version); > + new_h->version = cpu_to_le16(orig_h->version); > + new_h->log_length = cpu_to_le32(orig_h->log_length); > + new_h->log_offset = cpu_to_le64(orig_h->log_offset); > +} > + > +/* Update the VHDX headers > + * > + * This follows the VHDX spec procedures for header updates. > + * > + * - non-current header is updated with largest sequence number > + */ > +static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s, bool rw) > +{ > + int ret = 0; > + int hdr_idx = 0; > + uint64_t header_offset = VHDX_HEADER1_OFFSET; > + > + VHDXHeader *active_header; > + VHDXHeader *inactive_header; > + VHDXHeader header_le; > + uint8_t *buffer; > + > + /* operate on the non-current header */ > + if (s->curr_header == 0) { > + hdr_idx = 1; > + header_offset = VHDX_HEADER2_OFFSET; > + } > + > + active_header = s->headers[s->curr_header]; > + inactive_header = s->headers[hdr_idx]; > + > + inactive_header->sequence_number = active_header->sequence_number + 1; > + > + /* a new file guid must be generate before any file write, including > + * headers */ > + memcpy(&inactive_header->file_write_guid, &s->session_guid, > + sizeof(MSGUID)); > + > + /* a new data guid only needs to be generate before any guest-visible > + * writes, so update it if the image is opened r/w. */ > + if (rw) { > + vhdx_guid_generate(&inactive_header->data_write_guid); > + } > + > + /* the header checksum is not over just the packed size of VHDXHeader, > + * but rather over the entire 'reserved' range for the header, which is > + * 4KB (VHDX_HEADER_SIZE). */ > + > + buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE); > + /* we can't assume the extra reserved bytes are 0 */ > + ret = bdrv_pread(bs->file, header_offset, buffer, VHDX_HEADER_SIZE); > + if (ret < 0) { > + goto fail; > + } > + /* overwrite the actual VHDXHeader portion */ > + memcpy(buffer, inactive_header, sizeof(VHDXHeader)); > + inactive_header->checksum = vhdx_update_checksum(buffer, > + VHDX_HEADER_SIZE, 4); > + vhdx_header_le_export(inactive_header, &header_le); > + bdrv_pwrite_sync(bs->file, header_offset, &header_le, sizeof(VHDXHeader)); > + s->curr_header = hdr_idx; > + > +fail: Labeling it "fail:" is a bit misleading as normal path ends here too. > + qemu_vfree(buffer); > + return ret; > +} > + > +/* > + * The VHDX spec calls for header updates to be performed twice, so that both > + * the current and non-current header have valid info > + */ > +static int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw) > +{ > + int ret; > + > + ret = vhdx_update_header(bs, s, rw); > + if (ret < 0) { > + return ret; > + } > + ret = vhdx_update_header(bs, s, rw); > + return ret; > +} > > /* opens the specified header block from the VHDX file header section */ > static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s) > @@ -739,6 +888,11 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) > goto fail; > } > > + /* This is used for any header updates, for the file_write_guid. > + * The spec dictates that a new value should be used for the first > + * header update */ > + vhdx_guid_generate(&s->session_guid); > + > ret = vhdx_parse_header(bs, s); > if (ret) { > goto fail; > @@ -801,8 +955,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) > } > > if (flags & BDRV_O_RDWR) { > - ret = -ENOTSUP; > - goto fail; > + vhdx_update_headers(bs, s, false); > } > > /* TODO: differencing files, write */ > diff --git a/block/vhdx.h b/block/vhdx.h > index 1dbb320..3999cb1 100644 > --- a/block/vhdx.h > +++ b/block/vhdx.h > @@ -309,17 +309,27 @@ typedef struct QEMU_PACKED VHDXParentLocatorEntry { > /* ----- END VHDX SPECIFICATION STRUCTURES ---- */ > > > +void vhdx_guid_generate(MSGUID *guid); > + > +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset); > uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, > int crc_offset); > > bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset); > > > -static void leguid_to_cpus(MSGUID *guid) > +static inline void leguid_to_cpus(MSGUID *guid) > { > le32_to_cpus(&guid->data1); > le16_to_cpus(&guid->data2); > le16_to_cpus(&guid->data3); > } > > +static inline void cpu_to_leguids(MSGUID *guid) > +{ > + cpu_to_le32s(&guid->data1); > + cpu_to_le16s(&guid->data2); > + cpu_to_le16s(&guid->data3); > +} > + > #endif > diff --git a/configure b/configure > index 877a821..821b790 100755 > --- a/configure > +++ b/configure > @@ -244,6 +244,7 @@ gtk="" > gtkabi="2.0" > tpm="no" > libssh2="" > +vhdx="yes" > > # parse CC options first > for opt do > @@ -950,6 +951,11 @@ for opt do > ;; > --enable-libssh2) libssh2="yes" > ;; > + --enable-vhdx) vhdx="yes" ; > + uuid="yes" > + ;; > + --disable-vhdx) vhdx="no" > + ;; > *) echo "ERROR: unknown option $opt"; show_help="yes" > ;; > esac > @@ -1166,6 +1172,8 @@ echo " --gcov=GCOV use specified gcov [$gcov_tool]" > echo " --enable-tpm enable TPM support" > echo " --disable-libssh2 disable ssh block device support" > echo " --enable-libssh2 enable ssh block device support" > +echo " --disable-vhdx disables support for the Microsoft VHDX image format" > +echo " --enable-vhdx enable support for the Microsoft VHDX image format" > echo "" > echo "NOTE: The object files are built at the place where configure is launched" > exit 1 > @@ -3622,6 +3630,7 @@ echo "TPM support $tpm" > echo "libssh2 support $libssh2" > echo "TPM passthrough $tpm_passthrough" > echo "QOM debugging $qom_cast_debug" > +echo "vhdx $vhdx" > > if test "$sdl_too_old" = "yes"; then > echo "-> Your SDL version is too old - please upgrade to have SDL support" > @@ -4012,6 +4021,10 @@ if test "$virtio_blk_data_plane" = "yes" ; then > echo 'CONFIG_VIRTIO_BLK_DATA_PLANE=$(CONFIG_VIRTIO)' >> $config_host_mak > fi > > +if test "$vhdx" = "yes" ; then > + echo "CONFIG_VHDX=y" >> $config_host_mak > +fi > + > # USB host support > case "$usb" in > linux) > -- > 1.8.1.4 > >
On Fri, Jul 26, 2013 at 02:49:04PM +0800, Fam Zheng wrote: > On Wed, 07/24 13:54, Jeff Cody wrote: > > This adds the ability to update the headers in a VHDX image, including > > generating a new MS-compatible GUID. > > > > As VHDX depends on uuid.h, VHDX is now a configurable build option. If > > VHDX support is enabled, that will also enable uuid as well. The > > default is to have VHDX enabled. > > > > To enable/disable VHDX: --enable-vhdx, --disable-vhdx > > > > Signed-off-by: Jeff Cody <jcody@redhat.com> > > --- > > block/Makefile.objs | 2 +- > > block/vhdx.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++- > > block/vhdx.h | 12 +++- > > configure | 13 +++++ > > 4 files changed, 180 insertions(+), 4 deletions(-) > > > > diff --git a/block/Makefile.objs b/block/Makefile.objs > > index 4cf9aa4..e5e54e6 100644 > > --- a/block/Makefile.objs > > +++ b/block/Makefile.objs > > @@ -2,7 +2,7 @@ block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat > > block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o > > block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o > > block-obj-y += qed-check.o > > -block-obj-y += vhdx.o > > +block-obj-$(CONFIG_VHDX) += vhdx.o > > block-obj-y += parallels.o blkdebug.o blkverify.o > > block-obj-y += snapshot.o qapi.o > > block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o > > diff --git a/block/vhdx.c b/block/vhdx.c > > index 56bc88e..13e486d 100644 > > --- a/block/vhdx.c > > +++ b/block/vhdx.c > > @@ -21,6 +21,7 @@ > > #include "qemu/crc32c.h" > > #include "block/vhdx.h" > > > > +#include <uuid/uuid.h> > > > > /* Several metadata and region table data entries are identified by > > * guids in a MS-specific GUID format. */ > > @@ -156,11 +157,40 @@ typedef struct BDRVVHDXState { > > VHDXBatEntry *bat; > > uint64_t bat_offset; > > > > + MSGUID session_guid; > > + > > + > > VHDXParentLocatorHeader parent_header; > > VHDXParentLocatorEntry *parent_entries; > > > > } BDRVVHDXState; > > > > +/* Calculates new checksum. > > + * > > + * Zero is substituted during crc calculation for the original crc field > > + * crc_offset: byte offset in buf of the buffer crc > > + * buf: buffer pointer > > + * size: size of buffer (must be > crc_offset+4) > > + * > > + * Note: The resulting checksum is in the CPU endianness, not necessarily > > + * in the file format endianness (LE). Any header export to disk should > > + * make sure that vhdx_header_le_export() is used to convert to the > > + * correct endianness > > + */ > > +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset) > > +{ > > + uint32_t crc; > > + > > + assert(buf != NULL); > > + assert(size > (crc_offset + 4)); > > + > > + memset(buf + crc_offset, 0, sizeof(crc)); > > + crc = crc32c(0xffffffff, buf, size); > > + memcpy(buf + crc_offset, &crc, sizeof(crc)); > > + > > + return crc; > > +} > > + > > uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, > > int crc_offset) > > { > > @@ -212,6 +242,24 @@ bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset) > > > > > > /* > > + * This generates a UUID that is compliant with the MS GUIDs used > > + * in the VHDX spec (and elsewhere). > > + * > > + * We can do this with uuid_generate if uuid.h is present, > > + * however not all systems have uuid and the generation is > > + * pretty straightforward for the DCE + random usage case > > + * > > + */ > > +void vhdx_guid_generate(MSGUID *guid) > > +{ > > + uuid_t uuid; > > + assert(guid != NULL); > > + > > + uuid_generate(uuid); > > + memcpy(guid, uuid, 16); > > +} > > + > > +/* > > * Per the MS VHDX Specification, for every VHDX file: > > * - The header section is fixed size - 1 MB > > * - The header section is always the first "object" > > @@ -249,6 +297,107 @@ static void vhdx_header_le_import(VHDXHeader *h) > > le64_to_cpus(&h->log_offset); > > } > > > > +/* All VHDX structures on disk are little endian */ > > +static void vhdx_header_le_export(VHDXHeader *orig_h, VHDXHeader *new_h) > > +{ > > + assert(orig_h != NULL); > > + assert(new_h != NULL); > > + > > + new_h->signature = cpu_to_le32(orig_h->signature); > > + new_h->checksum = cpu_to_le32(orig_h->checksum); > > + new_h->sequence_number = cpu_to_le64(orig_h->sequence_number); > > + > > + memcpy(&new_h->file_write_guid, &orig_h->file_write_guid, sizeof(MSGUID)); > > + memcpy(&new_h->data_write_guid, &orig_h->data_write_guid, sizeof(MSGUID)); > > + memcpy(&new_h->log_guid, &orig_h->log_guid, sizeof(MSGUID)); > > + > > + cpu_to_leguids(&new_h->file_write_guid); > > + cpu_to_leguids(&new_h->data_write_guid); > > + cpu_to_leguids(&new_h->log_guid); > > + > > + new_h->log_version = cpu_to_le16(orig_h->log_version); > > + new_h->version = cpu_to_le16(orig_h->version); > > + new_h->log_length = cpu_to_le32(orig_h->log_length); > > + new_h->log_offset = cpu_to_le64(orig_h->log_offset); > > +} > > + > > +/* Update the VHDX headers > > + * > > + * This follows the VHDX spec procedures for header updates. > > + * > > + * - non-current header is updated with largest sequence number > > + */ > > +static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s, bool rw) > > +{ > > + int ret = 0; > > + int hdr_idx = 0; > > + uint64_t header_offset = VHDX_HEADER1_OFFSET; > > + > > + VHDXHeader *active_header; > > + VHDXHeader *inactive_header; > > + VHDXHeader header_le; > > + uint8_t *buffer; > > + > > + /* operate on the non-current header */ > > + if (s->curr_header == 0) { > > + hdr_idx = 1; > > + header_offset = VHDX_HEADER2_OFFSET; > > + } > > + > > + active_header = s->headers[s->curr_header]; > > + inactive_header = s->headers[hdr_idx]; > > + > > + inactive_header->sequence_number = active_header->sequence_number + 1; > > + > > + /* a new file guid must be generate before any file write, including > > + * headers */ > > + memcpy(&inactive_header->file_write_guid, &s->session_guid, > > + sizeof(MSGUID)); > > + > > + /* a new data guid only needs to be generate before any guest-visible > > + * writes, so update it if the image is opened r/w. */ > > + if (rw) { > > + vhdx_guid_generate(&inactive_header->data_write_guid); > > + } > > + > > + /* the header checksum is not over just the packed size of VHDXHeader, > > + * but rather over the entire 'reserved' range for the header, which is > > + * 4KB (VHDX_HEADER_SIZE). */ > > + > > + buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE); > > + /* we can't assume the extra reserved bytes are 0 */ > > + ret = bdrv_pread(bs->file, header_offset, buffer, VHDX_HEADER_SIZE); > > + if (ret < 0) { > > + goto fail; > > + } > > + /* overwrite the actual VHDXHeader portion */ > > + memcpy(buffer, inactive_header, sizeof(VHDXHeader)); > > + inactive_header->checksum = vhdx_update_checksum(buffer, > > + VHDX_HEADER_SIZE, 4); > > + vhdx_header_le_export(inactive_header, &header_le); > > + bdrv_pwrite_sync(bs->file, header_offset, &header_le, sizeof(VHDXHeader)); > > + s->curr_header = hdr_idx; > > + > > +fail: > > Labeling it "fail:" is a bit misleading as normal path ends here too. > Good point; I'll change that to just be 'exit'. > > + qemu_vfree(buffer); > > + return ret; > > +} > > + > > +/* > > + * The VHDX spec calls for header updates to be performed twice, so that both > > + * the current and non-current header have valid info > > + */ > > +static int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw) > > +{ > > + int ret; > > + > > + ret = vhdx_update_header(bs, s, rw); > > + if (ret < 0) { > > + return ret; > > + } > > + ret = vhdx_update_header(bs, s, rw); > > + return ret; > > +} > > > > /* opens the specified header block from the VHDX file header section */ > > static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s) > > @@ -739,6 +888,11 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) > > goto fail; > > } > > > > + /* This is used for any header updates, for the file_write_guid. > > + * The spec dictates that a new value should be used for the first > > + * header update */ > > + vhdx_guid_generate(&s->session_guid); > > + > > ret = vhdx_parse_header(bs, s); > > if (ret) { > > goto fail; > > @@ -801,8 +955,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) > > } > > > > if (flags & BDRV_O_RDWR) { > > - ret = -ENOTSUP; > > - goto fail; > > + vhdx_update_headers(bs, s, false); > > } > > > > /* TODO: differencing files, write */ > > diff --git a/block/vhdx.h b/block/vhdx.h > > index 1dbb320..3999cb1 100644 > > --- a/block/vhdx.h > > +++ b/block/vhdx.h > > @@ -309,17 +309,27 @@ typedef struct QEMU_PACKED VHDXParentLocatorEntry { > > /* ----- END VHDX SPECIFICATION STRUCTURES ---- */ > > > > > > +void vhdx_guid_generate(MSGUID *guid); > > + > > +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset); > > uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, > > int crc_offset); > > > > bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset); > > > > > > -static void leguid_to_cpus(MSGUID *guid) > > +static inline void leguid_to_cpus(MSGUID *guid) > > { > > le32_to_cpus(&guid->data1); > > le16_to_cpus(&guid->data2); > > le16_to_cpus(&guid->data3); > > } > > > > +static inline void cpu_to_leguids(MSGUID *guid) > > +{ > > + cpu_to_le32s(&guid->data1); > > + cpu_to_le16s(&guid->data2); > > + cpu_to_le16s(&guid->data3); > > +} > > + > > #endif > > diff --git a/configure b/configure > > index 877a821..821b790 100755 > > --- a/configure > > +++ b/configure > > @@ -244,6 +244,7 @@ gtk="" > > gtkabi="2.0" > > tpm="no" > > libssh2="" > > +vhdx="yes" > > > > # parse CC options first > > for opt do > > @@ -950,6 +951,11 @@ for opt do > > ;; > > --enable-libssh2) libssh2="yes" > > ;; > > + --enable-vhdx) vhdx="yes" ; > > + uuid="yes" > > + ;; > > + --disable-vhdx) vhdx="no" > > + ;; > > *) echo "ERROR: unknown option $opt"; show_help="yes" > > ;; > > esac > > @@ -1166,6 +1172,8 @@ echo " --gcov=GCOV use specified gcov [$gcov_tool]" > > echo " --enable-tpm enable TPM support" > > echo " --disable-libssh2 disable ssh block device support" > > echo " --enable-libssh2 enable ssh block device support" > > +echo " --disable-vhdx disables support for the Microsoft VHDX image format" > > +echo " --enable-vhdx enable support for the Microsoft VHDX image format" > > echo "" > > echo "NOTE: The object files are built at the place where configure is launched" > > exit 1 > > @@ -3622,6 +3630,7 @@ echo "TPM support $tpm" > > echo "libssh2 support $libssh2" > > echo "TPM passthrough $tpm_passthrough" > > echo "QOM debugging $qom_cast_debug" > > +echo "vhdx $vhdx" > > > > if test "$sdl_too_old" = "yes"; then > > echo "-> Your SDL version is too old - please upgrade to have SDL support" > > @@ -4012,6 +4021,10 @@ if test "$virtio_blk_data_plane" = "yes" ; then > > echo 'CONFIG_VIRTIO_BLK_DATA_PLANE=$(CONFIG_VIRTIO)' >> $config_host_mak > > fi > > > > +if test "$vhdx" = "yes" ; then > > + echo "CONFIG_VHDX=y" >> $config_host_mak > > +fi > > + > > # USB host support > > case "$usb" in > > linux) > > -- > > 1.8.1.4 > > > > > > -- > Fam
diff --git a/block/Makefile.objs b/block/Makefile.objs index 4cf9aa4..e5e54e6 100644 --- a/block/Makefile.objs +++ b/block/Makefile.objs @@ -2,7 +2,7 @@ block-obj-y += raw.o cow.o qcow.o vdi.o vmdk.o cloop.o dmg.o bochs.o vpc.o vvfat block-obj-y += qcow2.o qcow2-refcount.o qcow2-cluster.o qcow2-snapshot.o qcow2-cache.o block-obj-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o qed-cluster.o block-obj-y += qed-check.o -block-obj-y += vhdx.o +block-obj-$(CONFIG_VHDX) += vhdx.o block-obj-y += parallels.o blkdebug.o blkverify.o block-obj-y += snapshot.o qapi.o block-obj-$(CONFIG_WIN32) += raw-win32.o win32-aio.o diff --git a/block/vhdx.c b/block/vhdx.c index 56bc88e..13e486d 100644 --- a/block/vhdx.c +++ b/block/vhdx.c @@ -21,6 +21,7 @@ #include "qemu/crc32c.h" #include "block/vhdx.h" +#include <uuid/uuid.h> /* Several metadata and region table data entries are identified by * guids in a MS-specific GUID format. */ @@ -156,11 +157,40 @@ typedef struct BDRVVHDXState { VHDXBatEntry *bat; uint64_t bat_offset; + MSGUID session_guid; + + VHDXParentLocatorHeader parent_header; VHDXParentLocatorEntry *parent_entries; } BDRVVHDXState; +/* Calculates new checksum. + * + * Zero is substituted during crc calculation for the original crc field + * crc_offset: byte offset in buf of the buffer crc + * buf: buffer pointer + * size: size of buffer (must be > crc_offset+4) + * + * Note: The resulting checksum is in the CPU endianness, not necessarily + * in the file format endianness (LE). Any header export to disk should + * make sure that vhdx_header_le_export() is used to convert to the + * correct endianness + */ +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset) +{ + uint32_t crc; + + assert(buf != NULL); + assert(size > (crc_offset + 4)); + + memset(buf + crc_offset, 0, sizeof(crc)); + crc = crc32c(0xffffffff, buf, size); + memcpy(buf + crc_offset, &crc, sizeof(crc)); + + return crc; +} + uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, int crc_offset) { @@ -212,6 +242,24 @@ bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset) /* + * This generates a UUID that is compliant with the MS GUIDs used + * in the VHDX spec (and elsewhere). + * + * We can do this with uuid_generate if uuid.h is present, + * however not all systems have uuid and the generation is + * pretty straightforward for the DCE + random usage case + * + */ +void vhdx_guid_generate(MSGUID *guid) +{ + uuid_t uuid; + assert(guid != NULL); + + uuid_generate(uuid); + memcpy(guid, uuid, 16); +} + +/* * Per the MS VHDX Specification, for every VHDX file: * - The header section is fixed size - 1 MB * - The header section is always the first "object" @@ -249,6 +297,107 @@ static void vhdx_header_le_import(VHDXHeader *h) le64_to_cpus(&h->log_offset); } +/* All VHDX structures on disk are little endian */ +static void vhdx_header_le_export(VHDXHeader *orig_h, VHDXHeader *new_h) +{ + assert(orig_h != NULL); + assert(new_h != NULL); + + new_h->signature = cpu_to_le32(orig_h->signature); + new_h->checksum = cpu_to_le32(orig_h->checksum); + new_h->sequence_number = cpu_to_le64(orig_h->sequence_number); + + memcpy(&new_h->file_write_guid, &orig_h->file_write_guid, sizeof(MSGUID)); + memcpy(&new_h->data_write_guid, &orig_h->data_write_guid, sizeof(MSGUID)); + memcpy(&new_h->log_guid, &orig_h->log_guid, sizeof(MSGUID)); + + cpu_to_leguids(&new_h->file_write_guid); + cpu_to_leguids(&new_h->data_write_guid); + cpu_to_leguids(&new_h->log_guid); + + new_h->log_version = cpu_to_le16(orig_h->log_version); + new_h->version = cpu_to_le16(orig_h->version); + new_h->log_length = cpu_to_le32(orig_h->log_length); + new_h->log_offset = cpu_to_le64(orig_h->log_offset); +} + +/* Update the VHDX headers + * + * This follows the VHDX spec procedures for header updates. + * + * - non-current header is updated with largest sequence number + */ +static int vhdx_update_header(BlockDriverState *bs, BDRVVHDXState *s, bool rw) +{ + int ret = 0; + int hdr_idx = 0; + uint64_t header_offset = VHDX_HEADER1_OFFSET; + + VHDXHeader *active_header; + VHDXHeader *inactive_header; + VHDXHeader header_le; + uint8_t *buffer; + + /* operate on the non-current header */ + if (s->curr_header == 0) { + hdr_idx = 1; + header_offset = VHDX_HEADER2_OFFSET; + } + + active_header = s->headers[s->curr_header]; + inactive_header = s->headers[hdr_idx]; + + inactive_header->sequence_number = active_header->sequence_number + 1; + + /* a new file guid must be generate before any file write, including + * headers */ + memcpy(&inactive_header->file_write_guid, &s->session_guid, + sizeof(MSGUID)); + + /* a new data guid only needs to be generate before any guest-visible + * writes, so update it if the image is opened r/w. */ + if (rw) { + vhdx_guid_generate(&inactive_header->data_write_guid); + } + + /* the header checksum is not over just the packed size of VHDXHeader, + * but rather over the entire 'reserved' range for the header, which is + * 4KB (VHDX_HEADER_SIZE). */ + + buffer = qemu_blockalign(bs, VHDX_HEADER_SIZE); + /* we can't assume the extra reserved bytes are 0 */ + ret = bdrv_pread(bs->file, header_offset, buffer, VHDX_HEADER_SIZE); + if (ret < 0) { + goto fail; + } + /* overwrite the actual VHDXHeader portion */ + memcpy(buffer, inactive_header, sizeof(VHDXHeader)); + inactive_header->checksum = vhdx_update_checksum(buffer, + VHDX_HEADER_SIZE, 4); + vhdx_header_le_export(inactive_header, &header_le); + bdrv_pwrite_sync(bs->file, header_offset, &header_le, sizeof(VHDXHeader)); + s->curr_header = hdr_idx; + +fail: + qemu_vfree(buffer); + return ret; +} + +/* + * The VHDX spec calls for header updates to be performed twice, so that both + * the current and non-current header have valid info + */ +static int vhdx_update_headers(BlockDriverState *bs, BDRVVHDXState *s, bool rw) +{ + int ret; + + ret = vhdx_update_header(bs, s, rw); + if (ret < 0) { + return ret; + } + ret = vhdx_update_header(bs, s, rw); + return ret; +} /* opens the specified header block from the VHDX file header section */ static int vhdx_parse_header(BlockDriverState *bs, BDRVVHDXState *s) @@ -739,6 +888,11 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) goto fail; } + /* This is used for any header updates, for the file_write_guid. + * The spec dictates that a new value should be used for the first + * header update */ + vhdx_guid_generate(&s->session_guid); + ret = vhdx_parse_header(bs, s); if (ret) { goto fail; @@ -801,8 +955,7 @@ static int vhdx_open(BlockDriverState *bs, QDict *options, int flags) } if (flags & BDRV_O_RDWR) { - ret = -ENOTSUP; - goto fail; + vhdx_update_headers(bs, s, false); } /* TODO: differencing files, write */ diff --git a/block/vhdx.h b/block/vhdx.h index 1dbb320..3999cb1 100644 --- a/block/vhdx.h +++ b/block/vhdx.h @@ -309,17 +309,27 @@ typedef struct QEMU_PACKED VHDXParentLocatorEntry { /* ----- END VHDX SPECIFICATION STRUCTURES ---- */ +void vhdx_guid_generate(MSGUID *guid); + +uint32_t vhdx_update_checksum(uint8_t *buf, size_t size, int crc_offset); uint32_t vhdx_checksum_calc(uint32_t crc, uint8_t *buf, size_t size, int crc_offset); bool vhdx_checksum_is_valid(uint8_t *buf, size_t size, int crc_offset); -static void leguid_to_cpus(MSGUID *guid) +static inline void leguid_to_cpus(MSGUID *guid) { le32_to_cpus(&guid->data1); le16_to_cpus(&guid->data2); le16_to_cpus(&guid->data3); } +static inline void cpu_to_leguids(MSGUID *guid) +{ + cpu_to_le32s(&guid->data1); + cpu_to_le16s(&guid->data2); + cpu_to_le16s(&guid->data3); +} + #endif diff --git a/configure b/configure index 877a821..821b790 100755 --- a/configure +++ b/configure @@ -244,6 +244,7 @@ gtk="" gtkabi="2.0" tpm="no" libssh2="" +vhdx="yes" # parse CC options first for opt do @@ -950,6 +951,11 @@ for opt do ;; --enable-libssh2) libssh2="yes" ;; + --enable-vhdx) vhdx="yes" ; + uuid="yes" + ;; + --disable-vhdx) vhdx="no" + ;; *) echo "ERROR: unknown option $opt"; show_help="yes" ;; esac @@ -1166,6 +1172,8 @@ echo " --gcov=GCOV use specified gcov [$gcov_tool]" echo " --enable-tpm enable TPM support" echo " --disable-libssh2 disable ssh block device support" echo " --enable-libssh2 enable ssh block device support" +echo " --disable-vhdx disables support for the Microsoft VHDX image format" +echo " --enable-vhdx enable support for the Microsoft VHDX image format" echo "" echo "NOTE: The object files are built at the place where configure is launched" exit 1 @@ -3622,6 +3630,7 @@ echo "TPM support $tpm" echo "libssh2 support $libssh2" echo "TPM passthrough $tpm_passthrough" echo "QOM debugging $qom_cast_debug" +echo "vhdx $vhdx" if test "$sdl_too_old" = "yes"; then echo "-> Your SDL version is too old - please upgrade to have SDL support" @@ -4012,6 +4021,10 @@ if test "$virtio_blk_data_plane" = "yes" ; then echo 'CONFIG_VIRTIO_BLK_DATA_PLANE=$(CONFIG_VIRTIO)' >> $config_host_mak fi +if test "$vhdx" = "yes" ; then + echo "CONFIG_VHDX=y" >> $config_host_mak +fi + # USB host support case "$usb" in linux)
This adds the ability to update the headers in a VHDX image, including generating a new MS-compatible GUID. As VHDX depends on uuid.h, VHDX is now a configurable build option. If VHDX support is enabled, that will also enable uuid as well. The default is to have VHDX enabled. To enable/disable VHDX: --enable-vhdx, --disable-vhdx Signed-off-by: Jeff Cody <jcody@redhat.com> --- block/Makefile.objs | 2 +- block/vhdx.c | 157 +++++++++++++++++++++++++++++++++++++++++++++++++++- block/vhdx.h | 12 +++- configure | 13 +++++ 4 files changed, 180 insertions(+), 4 deletions(-)