Re: [Qemu-devel] [PATCH] Virt: ACPI: fix qemu assert due to re-assigned table data address

[Andrew Jones]

On Fri, Dec 22, 2017 at 02:52:47PM +0800, Shannon Zhao wrote:
> acpi_data_push uses g_array_set_size to resize the memory size. If there is no
> enough contiguous memory, the address will be changed. If we use the old 
> value,
> it will assert.
> qemu-kvm: hw/acpi/bios-linker-loader.c:214: bios_linker_loader_add_checksum:
> Assertion `start_offset < file->blob->len' failed.`
> 
> Signed-off-by: Shannon Zhao <address@hidden>
> ---
>  hw/arm/virt-acpi-build.c | 18 +++++++++++-------
>  1 file changed, 11 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index 3d78ff6..5901142 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -453,6 +453,7 @@ build_spcr(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>      AcpiSerialPortConsoleRedirection *spcr;
>      const MemMapEntry *uart_memmap = &vms->memmap[VIRT_UART];
>      int irq = vms->irqmap[VIRT_UART] + ARM_SPI_BASE;
> +    int spcr_start = table_data->len;
>  
>      spcr = acpi_data_push(table_data, sizeof(*spcr));
>  
> @@ -476,8 +477,8 @@ build_spcr(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>      spcr->pci_device_id = 0xffff;  /* PCI Device ID: not a PCI device */
>      spcr->pci_vendor_id = 0xffff;  /* PCI Vendor ID: not a PCI device */
>  
> -    build_header(linker, table_data, (void *)spcr, "SPCR", sizeof(*spcr), 2,
> -                 NULL, NULL);
> +    build_header(linker, table_data, (void *)(table_data->data + spcr_start),
> +                 "SPCR", table_data->len - spcr_start, 2, NULL, NULL);
>  }

We don't need to change build_spcr(), as acpi_data_push() is only called
once, so spcr == new table_data->data + old table_data->len and new
table_data->len - spcr == sizeof(*spcr) (the size used in the only
acpi_data_push() call)

>  
>  static void
> @@ -512,8 +513,8 @@ build_srat(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>          mem_base += numa_info[i].node_mem;
>      }
>  
> -    build_header(linker, table_data, (void *)srat, "SRAT",
> -                 table_data->len - srat_start, 3, NULL, NULL);
> +    build_header(linker, table_data, (void *)(table_data->data + srat_start),
> +                 "SRAT", table_data->len - srat_start, 3, NULL, NULL);

Yes, we need this fix, as there are many acpi_data_push() calls in this
function. I guess this was the table that triggered the assert.

>  }
>  
>  static void
> @@ -522,6 +523,7 @@ build_mcfg(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>      AcpiTableMcfg *mcfg;
>      const MemMapEntry *memmap = vms->memmap;
>      int len = sizeof(*mcfg) + sizeof(mcfg->allocation[0]);
> +    int mcfg_start = table_data->len;
>  
>      mcfg = acpi_data_push(table_data, len);
>      mcfg->allocation[0].address = cpu_to_le64(memmap[VIRT_PCIE_ECAM].base);
> @@ -532,7 +534,8 @@ build_mcfg(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>      mcfg->allocation[0].end_bus_number = (memmap[VIRT_PCIE_ECAM].size
>                                            / PCIE_MMCFG_SIZE_MIN) - 1;
>  
> -    build_header(linker, table_data, (void *)mcfg, "MCFG", len, 1, NULL, 
> NULL);
> +    build_header(linker, table_data, (void *)(table_data->data + mcfg_start),
> +                 "MCFG", len, 1, NULL, NULL);
>  }

No need to change this one.

>  
>  /* GTDT */
> @@ -651,6 +654,7 @@ build_madt(GArray *table_data, BIOSLinker *linker, 
> VirtMachineState *vms)
>  static void build_fadt(GArray *table_data, BIOSLinker *linker,
>                         VirtMachineState *vms, unsigned dsdt_tbl_offset)
>  {
> +    int fadt_start = table_data->len;
>      AcpiFadtDescriptorRev5_1 *fadt = acpi_data_push(table_data, 
> sizeof(*fadt));
>      unsigned xdsdt_entry_offset = (char *)&fadt->x_dsdt - table_data->data;
>      uint16_t bootflags;
> @@ -681,8 +685,8 @@ static void build_fadt(GArray *table_data, BIOSLinker 
> *linker,
>          ACPI_BUILD_TABLE_FILE, xdsdt_entry_offset, sizeof(fadt->x_dsdt),
>          ACPI_BUILD_TABLE_FILE, dsdt_tbl_offset);
>  
> -    build_header(linker, table_data,
> -                 (void *)fadt, "FACP", sizeof(*fadt), 5, NULL, NULL);
> +    build_header(linker, table_data, (void *)(table_data->data + fadt_start),
> +                 "FACP", table_data->len - fadt_start, 5, NULL, NULL);
>  }

No need to change this one either.

>  
>  /* DSDT */
> -- 
> 2.0.4
> 
>

Please respin only changing the one that needs the fix.

Thanks,
drew