Re: [PATCH RESEND v2 1/3] acpi/ghes: Extend acpi_ghes_memory_errors() to support multiple CPERs

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Tue,  7 Oct 2025 16:08:08 +1000
Gavin Shan <gshan@redhat.com> wrote:

> In the situation where host and guest has 64KB and 4KB page sizes, one
> error on the host's page affects 16 guest's pages. we need to send 16
> consective errors in this specific case.

Hi Gavin,

Sorry this one has been on my to review list far too long.

> 
> Extend acpi_ghes_memory_errors() to support multiple CPERs after the
> hunk of code to generate the GHES error status is pulled out from
> ghes_gen_err_data_uncorrectable_recoverable().

I think this description needs to be more detailed wrt to how those
multiple CPERs are handled.  Specifically that they are in a single
error status block (so should only represent related errors.)

This is to make it clear this isn't queuing events, but instead just
presenting them as one block.

> 
> No functional changes intended.
> 
> Signed-off-by: Gavin Shan <gshan@redhat.com>
> ---
>  hw/acpi/ghes-stub.c    |  2 +-
>  hw/acpi/ghes.c         | 27 ++++++++++++++-------------
>  include/hw/acpi/ghes.h |  2 +-
>  target/arm/kvm.c       |  7 ++++++-
>  4 files changed, 22 insertions(+), 16 deletions(-)

> diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> index 06555905ce..045b77715f 100644
> --- a/hw/acpi/ghes.c
> +++ b/hw/acpi/ghes.c
> @@ -214,18 +214,13 @@ static void acpi_ghes_build_append_mem_cper(GArray *table,
>  
>  static void
>  ghes_gen_err_data_uncorrectable_recoverable(GArray *block,
> -                                            const uint8_t *section_type,
> -                                            int data_length)
> +                                            const uint8_t *section_type)
>  {
>      /* invalid fru id: ACPI 4.0: 17.3.2.6.1 Generic Error Data,
>       * Table 17-13 Generic Error Data Entry
>       */
>      QemuUUID fru_id = {};
>  
> -    /* Build the new generic error status block header */
> -    acpi_ghes_generic_error_status(block, ACPI_GEBS_UNCORRECTABLE,
> -        0, 0, data_length, ACPI_CPER_SEV_RECOVERABLE);
> -]

With this bit gone, is it worth having the helper?  Perhaps just move
the remains to where it is called.

>      /* Build this new generic error data entry header */
>      acpi_ghes_generic_error_data(block, section_type,
>          ACPI_CPER_SEV_RECOVERABLE, 0, 0,

> diff --git a/target/arm/kvm.c b/target/arm/kvm.c
> index 4f769d69b3..9a47ac9e3a 100644
> --- a/target/arm/kvm.c
> +++ b/target/arm/kvm.c
> @@ -2434,6 +2434,7 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
>      ram_addr_t ram_addr;
>      hwaddr paddr;
>      AcpiGhesState *ags;
> +    GArray *addresses;
>  
>      assert(code == BUS_MCEERR_AR || code == BUS_MCEERR_AO);
>  
> @@ -2442,6 +2443,7 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
>          ram_addr = qemu_ram_addr_from_host(addr);
>          if (ram_addr != RAM_ADDR_INVALID &&
>              kvm_physical_memory_addr_from_host(c->kvm_state, addr, &paddr)) {
> +            addresses = g_array_new(false, false, sizeof(paddr));

Given you are going to free in all paths, maybe a g_autofree?

Also, we know this only grows to a fixed max size (16 after patch 3), so maybe just
provide a hwaddr paddrs[16]; and pass forwards the count?

>              kvm_hwpoison_page_add(ram_addr);
>              /*
>               * If this is a BUS_MCEERR_AR, we know we have been called
> @@ -2454,16 +2456,19 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
>               * later from the main thread, so doing the injection of
>               * the error would be more complicated.
>               */
> +            g_array_append_vals(addresses, &paddr, 1);
>              if (code == BUS_MCEERR_AR) {
>                  kvm_cpu_synchronize_state(c);
>                  if (!acpi_ghes_memory_errors(ags, ACPI_HEST_SRC_ID_SYNC,
> -                                             paddr)) {
> +                                             addresses)) {
>                      kvm_inject_arm_sea(c);
>                  } else {
>                      error_report("failed to record the error");
>                      abort();
>                  }
>              }
> +
> +            g_array_free(addresses, true);
>              return;
>          }
>          if (code == BUS_MCEERR_AO) {