From 3bb3006a632da5b11ec7a154d5b819b8bfab8dab Mon Sep 17 00:00:00 2001 From: Igor Mammedov Date: Mon, 17 Dec 2018 11:48:33 +0100 Subject: 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 Reviewed-by: Samuel Ortiz Signed-off-by: Samuel Ortiz Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/i386/acpi-build.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) 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); } -- cgit v1.1