Re: [PATCH RFCv2 1/4] hw/i386: add 4g boundary start to X86MachineState

[Igor Mammedov <imammedo@redhat.com>]

On Mon,  7 Feb 2022 20:24:19 +0000
Joao Martins <joao.m.martins@oracle.com> wrote:

> Rather than hardcoding the 4G boundary everywhere, introduce a
> X86MachineState property @above_4g_mem_start and use it
> accordingly.
> 
> This is in preparation for relocating ram-above-4g to be
> dynamically start at 1T on AMD platforms.
> 
> Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
> ---
>  hw/i386/acpi-build.c  | 2 +-
>  hw/i386/pc.c          | 9 +++++----
>  hw/i386/sgx.c         | 2 +-
>  hw/i386/x86.c         | 1 +
>  include/hw/i386/x86.h | 3 +++
>  5 files changed, 11 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index ebd47aa26fd8..4bf54ccdab91 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -2063,7 +2063,7 @@ build_srat(GArray *table_data, BIOSLinker *linker, MachineState *machine)
>                  build_srat_memory(table_data, mem_base, mem_len, i - 1,
>                                    MEM_AFFINITY_ENABLED);
>              }
> -            mem_base = 1ULL << 32;
> +            mem_base = x86ms->above_4g_mem_start;
>              mem_len = next_base - x86ms->below_4g_mem_size;
>              next_base = mem_base + mem_len;
>          }
> diff --git a/hw/i386/pc.c b/hw/i386/pc.c
> index c8696ac01e85..7de0e87f4a3f 100644
> --- a/hw/i386/pc.c
> +++ b/hw/i386/pc.c
> @@ -837,9 +837,10 @@ void pc_memory_init(PCMachineState *pcms,
>                                   machine->ram,
>                                   x86ms->below_4g_mem_size,
>                                   x86ms->above_4g_mem_size);
> -        memory_region_add_subregion(system_memory, 0x100000000ULL,
> +        memory_region_add_subregion(system_memory, x86ms->above_4g_mem_start,
>                                      ram_above_4g);
> -        e820_add_entry(0x100000000ULL, x86ms->above_4g_mem_size, E820_RAM);
> +        e820_add_entry(x86ms->above_4g_mem_start, x86ms->above_4g_mem_size,
> +                       E820_RAM);
>      }
>  
>      if (pcms->sgx_epc.size != 0) {
> @@ -880,7 +881,7 @@ void pc_memory_init(PCMachineState *pcms,
>              machine->device_memory->base = sgx_epc_above_4g_end(&pcms->sgx_epc);
>          } else {
>              machine->device_memory->base =
> -                0x100000000ULL + x86ms->above_4g_mem_size;
> +                x86ms->above_4g_mem_start + x86ms->above_4g_mem_size;
>          }
>  
>          machine->device_memory->base =
> @@ -972,7 +973,7 @@ uint64_t pc_pci_hole64_start(void)
>      } else if (pcms->sgx_epc.size != 0) {
>              hole64_start = sgx_epc_above_4g_end(&pcms->sgx_epc);
>      } else {
> -        hole64_start = 0x100000000ULL + x86ms->above_4g_mem_size;
> +        hole64_start = x86ms->above_4g_mem_start + x86ms->above_4g_mem_size;
>      }
>  
>      return ROUND_UP(hole64_start, 1 * GiB);
> diff --git a/hw/i386/sgx.c b/hw/i386/sgx.c
> index a2b318dd9387..164ee1ddb8de 100644
> --- a/hw/i386/sgx.c
> +++ b/hw/i386/sgx.c
> @@ -295,7 +295,7 @@ void pc_machine_init_sgx_epc(PCMachineState *pcms)
>          return;
>      }
>  
> -    sgx_epc->base = 0x100000000ULL + x86ms->above_4g_mem_size;
> +    sgx_epc->base = x86ms->above_4g_mem_start + x86ms->above_4g_mem_size;
>  
>      memory_region_init(&sgx_epc->mr, OBJECT(pcms), "sgx-epc", UINT64_MAX);
>      memory_region_add_subregion(get_system_memory(), sgx_epc->base,
> diff --git a/hw/i386/x86.c b/hw/i386/x86.c
> index b84840a1bb99..912e96718ee8 100644
> --- a/hw/i386/x86.c
> +++ b/hw/i386/x86.c
> @@ -1319,6 +1319,7 @@ static void x86_machine_initfn(Object *obj)
>      x86ms->oem_id = g_strndup(ACPI_BUILD_APPNAME6, 6);
>      x86ms->oem_table_id = g_strndup(ACPI_BUILD_APPNAME8, 8);
>      x86ms->bus_lock_ratelimit = 0;
> +    x86ms->above_4g_mem_start = 0x100000000ULL;
>  }
>  
>  static void x86_machine_class_init(ObjectClass *oc, void *data)
> diff --git a/include/hw/i386/x86.h b/include/hw/i386/x86.h
> index a145a303703f..2de7ec046b75 100644
> --- a/include/hw/i386/x86.h
> +++ b/include/hw/i386/x86.h
> @@ -58,6 +58,9 @@ struct X86MachineState {
>      /* RAM information (sizes, addresses, configuration): */
>      ram_addr_t below_4g_mem_size, above_4g_mem_size;
>  
> +    /* RAM information when there's a hole in 1Tb */

s/^^^/GPA of the part of initial RAM above 4G/

or something like that, it doesn't have anything to do with hole at 1Tb
on some hosts.

> +    ram_addr_t above_4g_mem_start;
> +
>      /* CPU and apic information: */
>      bool apic_xrupt_override;
>      unsigned pci_irq_mask;