Re: [PATCH for-6.0] x86: acpi: use offset instead of pointer when using build_header()

[Michael S. Tsirkin]

On Tue, Apr 13, 2021 at 07:14:00AM -0400, Igor Mammedov wrote:
> Do the same as in commit
>  (4d027afeb3a97 Virt: ACPI: fix qemu assert due to re-assigned table data 
> address)
> for remaining tables that happen to use saved at
> the beginning pointer to build header to avoid assert
> when table_data is relocated due to implicit re-size.
> 
> Reported-in: https://bugs.launchpad.net/bugs/1923497

Doesn't this fix the bug? If so -
Isn't this Fixes: ?

> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
> ---
> PS:
>  I have build_header() refactoring patch that requires offset
>  instead of pointer, to make it harder to misuse but it's
>  a bit intrusive for last minute fixes. So here goes simplified
>  variant, and I'll post refactoring patch for 6.1. later.
> ---
>  hw/acpi/aml-build.c  | 15 +++++++++------
>  hw/i386/acpi-build.c |  8 ++++++--
>  2 files changed, 15 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> index d33ce8954a..f0035d2b4a 100644
> --- a/hw/acpi/aml-build.c
> +++ b/hw/acpi/aml-build.c
> @@ -1830,6 +1830,7 @@ build_rsdt(GArray *table_data, BIOSLinker *linker, 
> GArray *table_offsets,
>      int i;
>      unsigned rsdt_entries_offset;
>      AcpiRsdtDescriptorRev1 *rsdt;
> +    int rsdt_start = table_data->len;
>      const unsigned table_data_len = (sizeof(uint32_t) * table_offsets->len);
>      const unsigned rsdt_entry_size = sizeof(rsdt->table_offset_entry[0]);
>      const size_t rsdt_len = sizeof(*rsdt) + table_data_len;
> @@ -1846,7 +1847,8 @@ build_rsdt(GArray *table_data, BIOSLinker *linker, 
> GArray *table_offsets,
>              ACPI_BUILD_TABLE_FILE, ref_tbl_offset);
>      }
>      build_header(linker, table_data,
> -                 (void *)rsdt, "RSDT", rsdt_len, 1, oem_id, oem_table_id);
> +                 (void *)(table_data->data + rsdt_start),
> +                 "RSDT", rsdt_len, 1, oem_id, oem_table_id);
>  }
>  
>  /* Build xsdt table */
> @@ -1857,6 +1859,7 @@ build_xsdt(GArray *table_data, BIOSLinker *linker, 
> GArray *table_offsets,
>      int i;
>      unsigned xsdt_entries_offset;
>      AcpiXsdtDescriptorRev2 *xsdt;
> +    int xsdt_start = table_data->len;
>      const unsigned table_data_len = (sizeof(uint64_t) * table_offsets->len);
>      const unsigned xsdt_entry_size = sizeof(xsdt->table_offset_entry[0]);
>      const size_t xsdt_len = sizeof(*xsdt) + table_data_len;
> @@ -1873,7 +1876,8 @@ build_xsdt(GArray *table_data, BIOSLinker *linker, 
> GArray *table_offsets,
>              ACPI_BUILD_TABLE_FILE, ref_tbl_offset);
>      }
>      build_header(linker, table_data,
> -                 (void *)xsdt, "XSDT", xsdt_len, 1, oem_id, oem_table_id);
> +                 (void *)(table_data->data + xsdt_start),
> +                 "XSDT", xsdt_len, 1, oem_id, oem_table_id);
>  }
>  
>  void build_srat_memory(AcpiSratMemoryAffinity *numamem, uint64_t base,
> @@ -2053,10 +2057,9 @@ void build_tpm2(GArray *table_data, BIOSLinker 
> *linker, GArray *tcpalog,
>      uint64_t control_area_start_address;
>      TPMIf *tpmif = tpm_find();
>      uint32_t start_method;
> -    void *tpm2_ptr;
>  
>      tpm2_start = table_data->len;
> -    tpm2_ptr = acpi_data_push(table_data, sizeof(AcpiTableHeader));
> +    acpi_data_push(table_data, sizeof(AcpiTableHeader));
>  
>      /* Platform Class */
>      build_append_int_noprefix(table_data, TPM2_ACPI_CLASS_CLIENT, 2);
> @@ -2095,8 +2098,8 @@ void build_tpm2(GArray *table_data, BIOSLinker *linker, 
> GArray *tcpalog,
>                                     log_addr_offset, 8,
>                                     ACPI_BUILD_TPMLOG_FILE, 0);
>      build_header(linker, table_data,
> -                 tpm2_ptr, "TPM2", table_data->len - tpm2_start, 4, oem_id,
> -                 oem_table_id);
> +                 (void *)(table_data->data + tpm2_start),
> +                 "TPM2", table_data->len - tpm2_start, 4, oem_id, 
> oem_table_id);
>  }
>  
>  Aml *build_crs(PCIHostState *host, CrsRangeSet *range_set, uint32_t 
> io_offset,
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index de98750aef..daaf8f473e 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1816,6 +1816,7 @@ build_hpet(GArray *table_data, BIOSLinker *linker, 
> const char *oem_id,
>             const char *oem_table_id)
>  {
>      Acpi20Hpet *hpet;
> +    int hpet_start = table_data->len;
>  
>      hpet = acpi_data_push(table_data, sizeof(*hpet));
>      /* Note timer_block_id value must be kept in sync with value advertised 
> by
> @@ -1824,13 +1825,15 @@ build_hpet(GArray *table_data, BIOSLinker *linker, 
> const char *oem_id,
>      hpet->timer_block_id = cpu_to_le32(0x8086a201);
>      hpet->addr.address = cpu_to_le64(HPET_BASE);
>      build_header(linker, table_data,
> -                 (void *)hpet, "HPET", sizeof(*hpet), 1, oem_id, 
> oem_table_id);
> +                 (void *)(table_data->data + hpet_start),
> +                 "HPET", sizeof(*hpet), 1, oem_id, oem_table_id);
>  }
>  
>  static void
>  build_tpm_tcpa(GArray *table_data, BIOSLinker *linker, GArray *tcpalog,
>                 const char *oem_id, const char *oem_table_id)
>  {
> +    int tcpa_start = table_data->len;
>      Acpi20Tcpa *tcpa = acpi_data_push(table_data, sizeof *tcpa);
>      unsigned log_addr_size = sizeof(tcpa->log_area_start_address);
>      unsigned log_addr_offset =
> @@ -1849,7 +1852,8 @@ build_tpm_tcpa(GArray *table_data, BIOSLinker *linker, 
> GArray *tcpalog,
>          ACPI_BUILD_TPMLOG_FILE, 0);
>  
>      build_header(linker, table_data,
> -                 (void *)tcpa, "TCPA", sizeof(*tcpa), 2, oem_id, 
> oem_table_id);
> +                 (void *)(table_data->data + tcpa_start),
> +                 "TCPA", sizeof(*tcpa), 2, oem_id, oem_table_id);
>  }
>  
>  #define HOLE_640K_START  (640 * KiB)
> -- 
> 2.27.0