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

[Shannon Zhao]

On 2017/12/26 19:48, Andrew Jones wrote:
> 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.
> 
Hi Andrew,

Thanks for your comments. What you said is right that only the
build_srat needs to be fixed but I thought we need to unify the style
and avoid new issues if add some acpi_data_push in other functions in
the future.

Thanks,
-- 
Shannon