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authorIgor Mammedov <imammedo@redhat.com>2018-12-17 11:48:33 +0100
committerMichael S. Tsirkin <mst@redhat.com>2018-12-19 16:48:16 -0500
commit3bb3006a632da5b11ec7a154d5b819b8bfab8dab (patch)
treecb70fe468a24caa6a665e07d1eaaf17848522edf /hw/i386
parent4774866457a675a751c38fb0d9ed09113777ec15 (diff)
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hw: i386: Use correct RSDT length for checksum
AcpiRsdpDescriptor describes revision 2 RSDP table so using sizeof(*rsdp) for checksum calculation isn't correct since we are adding extra 16 bytes. But acpi_data_push() zeroes out table, so just by luck we are summing up exta zeros which still yelds correct checksum. Fix it up by explicitly stating table size instead of using pointer arithmetics on stucture. PS: Extra 16 bytes are still wasted, but droping them will break migration for machines older than 2.3 due to size mismatch, for 2.3 and older it's not an issue since they are using resizable memory regions (a1666142d) for ACPI blobs. So keep wasting memory to avoid breaking old machines. Fixes: 72c194f7e (i386: ACPI table generation code from seabios) Signed-off-by: Igor Mammedov <imammedo@redhat.com> Reviewed-by: Samuel Ortiz <sameo@linux.intel.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw/i386')
-rw-r--r--hw/i386/acpi-build.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 35f17d0..fb87764 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2550,6 +2550,11 @@ build_amd_iommu(GArray *table_data, BIOSLinker *linker)
static void
build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset)
{
+ /* AcpiRsdpDescriptor describes revision 2 RSDP table and as result we
+ * allocate extra 16 bytes for pc/q35 RSDP rev1 as well. Keep extra 16 bytes
+ * wasted to make sure we won't breake migration for machine types older
+ * than 2.3 due to size mismatch.
+ */
AcpiRsdpDescriptor *rsdp = acpi_data_push(rsdp_table, sizeof *rsdp);
unsigned rsdt_pa_size = sizeof(rsdp->rsdt_physical_address);
unsigned rsdt_pa_offset =
@@ -2567,7 +2572,7 @@ build_rsdp(GArray *rsdp_table, BIOSLinker *linker, unsigned rsdt_tbl_offset)
/* Checksum to be filled by Guest linker */
bios_linker_loader_add_checksum(linker, ACPI_BUILD_RSDP_FILE,
- (char *)rsdp - rsdp_table->data, sizeof *rsdp,
+ (char *)rsdp - rsdp_table->data, 20 /* ACPI rev 1.0 RSDP size */,
(char *)&rsdp->checksum - rsdp_table->data);
}