jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
vpc: Require aligned size in .bdrv_co_create
Perform the rounding to match a CHS geometry only in the legacy code
path in .bdrv_co_create_opts. QMP now requires that the user already
passes a CHS aligned image size, unless force-size=true is given.
CHS alignment is required to make the image compatible with Virtual PC,
but not for use with newer Microsoft hypervisors.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
+82
-31
+82
-31
block/vpc.c
+82
-31
block/vpc.c
···
902
902
return ret;
903
903
}
904
904
905
+
static int calculate_rounded_image_size(BlockdevCreateOptionsVpc *vpc_opts,
906
+
uint16_t *out_cyls,
907
+
uint8_t *out_heads,
908
+
uint8_t *out_secs_per_cyl,
909
+
int64_t *out_total_sectors,
910
+
Error **errp)
911
+
{
912
+
int64_t total_size = vpc_opts->size;
913
+
uint16_t cyls = 0;
914
+
uint8_t heads = 0;
915
+
uint8_t secs_per_cyl = 0;
916
+
int64_t total_sectors;
917
+
int i;
918
+
919
+
/*
920
+
* Calculate matching total_size and geometry. Increase the number of
921
+
* sectors requested until we get enough (or fail). This ensures that
922
+
* qemu-img convert doesn't truncate images, but rather rounds up.
923
+
*
924
+
* If the image size can't be represented by a spec conformant CHS geometry,
925
+
* we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
926
+
* the image size from the VHD footer to calculate total_sectors.
927
+
*/
928
+
if (vpc_opts->force_size) {
929
+
/* This will force the use of total_size for sector count, below */
930
+
cyls = VHD_CHS_MAX_C;
931
+
heads = VHD_CHS_MAX_H;
932
+
secs_per_cyl = VHD_CHS_MAX_S;
933
+
} else {
934
+
total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE);
935
+
for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
936
+
calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl);
937
+
}
938
+
}
939
+
940
+
if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
941
+
total_sectors = total_size / BDRV_SECTOR_SIZE;
942
+
/* Allow a maximum disk size of 2040 GiB */
943
+
if (total_sectors > VHD_MAX_SECTORS) {
944
+
error_setg(errp, "Disk size is too large, max size is 2040 GiB");
945
+
return -EFBIG;
946
+
}
947
+
} else {
948
+
total_sectors = (int64_t) cyls * heads * secs_per_cyl;
949
+
}
950
+
951
+
*out_total_sectors = total_sectors;
952
+
if (out_cyls) {
953
+
*out_cyls = cyls;
954
+
*out_heads = heads;
955
+
*out_secs_per_cyl = secs_per_cyl;
956
+
}
957
+
958
+
return 0;
959
+
}
960
+
905
961
static int coroutine_fn vpc_co_create(BlockdevCreateOptions *opts,
906
962
Error **errp)
907
963
{
···
911
967
912
968
uint8_t buf[1024];
913
969
VHDFooter *footer = (VHDFooter *) buf;
914
-
int i;
915
970
uint16_t cyls = 0;
916
971
uint8_t heads = 0;
917
972
uint8_t secs_per_cyl = 0;
···
953
1008
}
954
1009
blk_set_allow_write_beyond_eof(blk, true);
955
1010
956
-
/*
957
-
* Calculate matching total_size and geometry. Increase the number of
958
-
* sectors requested until we get enough (or fail). This ensures that
959
-
* qemu-img convert doesn't truncate images, but rather rounds up.
960
-
*
961
-
* If the image size can't be represented by a spec conformant CHS geometry,
962
-
* we set the geometry to 65535 x 16 x 255 (CxHxS) sectors and use
963
-
* the image size from the VHD footer to calculate total_sectors.
964
-
*/
965
-
if (vpc_opts->force_size) {
966
-
/* This will force the use of total_size for sector count, below */
967
-
cyls = VHD_CHS_MAX_C;
968
-
heads = VHD_CHS_MAX_H;
969
-
secs_per_cyl = VHD_CHS_MAX_S;
970
-
} else {
971
-
total_sectors = MIN(VHD_MAX_GEOMETRY, total_size / BDRV_SECTOR_SIZE);
972
-
for (i = 0; total_sectors > (int64_t)cyls * heads * secs_per_cyl; i++) {
973
-
calculate_geometry(total_sectors + i, &cyls, &heads, &secs_per_cyl);
974
-
}
1011
+
/* Get geometry and check that it matches the image size*/
1012
+
ret = calculate_rounded_image_size(vpc_opts, &cyls, &heads, &secs_per_cyl,
1013
+
&total_sectors, errp);
1014
+
if (ret < 0) {
1015
+
goto out;
975
1016
}
976
1017
977
-
if ((int64_t)cyls * heads * secs_per_cyl == VHD_MAX_GEOMETRY) {
978
-
total_sectors = total_size / BDRV_SECTOR_SIZE;
979
-
/* Allow a maximum disk size of 2040 GiB */
980
-
if (total_sectors > VHD_MAX_SECTORS) {
981
-
error_setg(errp, "Disk size is too large, max size is 2040 GiB");
982
-
ret = -EFBIG;
983
-
goto out;
984
-
}
985
-
} else {
986
-
total_sectors = (int64_t)cyls * heads * secs_per_cyl;
987
-
total_size = total_sectors * BDRV_SECTOR_SIZE;
1018
+
if (total_size != total_sectors * BDRV_SECTOR_SIZE) {
1019
+
error_setg(errp, "The requested image size cannot be represented in "
1020
+
"CHS geometry");
1021
+
error_append_hint(errp, "Try size=%llu or force-size=on (the "
1022
+
"latter makes the image incompatible with "
1023
+
"Virtual PC)",
1024
+
total_sectors * BDRV_SECTOR_SIZE);
1025
+
ret = -EINVAL;
1026
+
goto out;
988
1027
}
989
1028
990
1029
/* Prepare the Hard Disk Footer */
···
1101
1140
assert(create_options->driver == BLOCKDEV_DRIVER_VPC);
1102
1141
create_options->u.vpc.size =
1103
1142
ROUND_UP(create_options->u.vpc.size, BDRV_SECTOR_SIZE);
1143
+
1144
+
if (!create_options->u.vpc.force_size) {
1145
+
int64_t total_sectors;
1146
+
ret = calculate_rounded_image_size(&create_options->u.vpc, NULL, NULL,
1147
+
NULL, &total_sectors, errp);
1148
+
if (ret < 0) {
1149
+
goto fail;
1150
+
}
1151
+
1152
+
create_options->u.vpc.size = total_sectors * BDRV_SECTOR_SIZE;
1153
+
}
1154
+
1104
1155
1105
1156
/* Create the vpc image (format layer) */
1106
1157
ret = vpc_co_create(create_options, errp);