From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37739) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gRJmW-0000oo-7q for qemu-devel@nongnu.org; Mon, 26 Nov 2018 11:30:45 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gRJmR-0004WD-Dy for qemu-devel@nongnu.org; Mon, 26 Nov 2018 11:30:44 -0500 From: Samuel Ortiz Date: Mon, 26 Nov 2018 17:29:36 +0100 Message-Id: <20181126162942.21258-4-sameo@linux.intel.com> In-Reply-To: <20181126162942.21258-1-sameo@linux.intel.com> References: <20181126162942.21258-1-sameo@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Qemu-devel] [PATCH 3/8] hw: i386: Use correct RSDT length for checksum List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Peter Maydell , Igor Mammedov , qemu-arm@nongnu.org, Shannon Zhao , Laurent Vivier , Richard Henderson , Paolo Bonzini , Ben Warren , Thomas Huth , Marcel Apfelbaum , Eduardo Habkost , "Michael S. Tsirkin" From: Igor Mammedov 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 --- 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 35f17d0d91..fb877648ac 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); } -- 2.19.1