Re: [Qemu-devel] [PATCH v17 10/10] target-arm: kvm64: handle SIGBUS signal from kernel or KVM

[Jonathan Cameron]

On Tue, 14 May 2019 04:18:23 -0700
Dongjiu Geng <address@hidden> wrote:

> Add SIGBUS signal handler. In this handler, it checks the SIGBUS type,
> translates the host VA delivered by host to guest PA, then fill this PA
> to guest APEI GHES memory, then notify guest according to the SIGBUS type.
> 
> If guest accesses the poisoned memory, it generates Synchronous External
> Abort(SEA). Then host kernel gets an APEI notification and call 
> memory_failure()
> to unmapped the affected page for the guest's stage 2, finally return
> to guest.
> 
> Guest continues to access PG_hwpoison page, it will trap to KVM as stage2 
> fault,
> then a SIGBUS_MCEERR_AR synchronous signal is delivered to Qemu, Qemu record 
> this
> error address into guest APEI GHES memory and notify guest using
> Synchronous-External-Abort(SEA).
> 
> Suggested-by: James Morse <address@hidden>
> Signed-off-by: Dongjiu Geng <address@hidden>
Hi Dongjiu,

Good to see this moving forwards again.

A few really minor things inline.

Thanks,

Jonathan

> ---
>  hw/acpi/acpi_ghes.c         | 177 
> ++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/acpi/acpi_ghes.h |   6 +-
>  include/sysemu/kvm.h        |   2 +-
>  target/arm/kvm64.c          |  39 ++++++++++
>  4 files changed, 222 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/acpi/acpi_ghes.c b/hw/acpi/acpi_ghes.c
> index d03e797..06b7374 100644
> --- a/hw/acpi/acpi_ghes.c
> +++ b/hw/acpi/acpi_ghes.c
> @@ -26,6 +26,101 @@
>  #include "sysemu/sysemu.h"
>  #include "qemu/error-report.h"
>  
> +/* UEFI 2.6: N.2.5 Memory Error Section */
> +static void build_append_mem_cper(GArray *table, uint64_t 
> error_physical_addr)
> +{
> +    /*
> +     * Memory Error Record
> +     */
> +    build_append_int_noprefix(table,
> +                 (1UL << 14) | /* Type Valid */
> +                 (1UL << 1) /* Physical Address Valid */,
> +                 8);
> +    /* Memory error status information */
> +    build_append_int_noprefix(table, 0, 8);
> +    /* The physical address at which the memory error occurred */
> +    build_append_int_noprefix(table, error_physical_addr, 8);
> +    build_append_int_noprefix(table, 0, 48);

This could do with a comment to say we are basically skipping all the
detailed information normally found in such a record.


> +    build_append_int_noprefix(table, 0 /* Unknown error */, 1);
> +    build_append_int_noprefix(table, 0, 7);
A similar comment for this last section would probably use useful as well.

> +}
> +
> +static int ghes_record_mem_error(uint64_t error_block_address,
> +                                    uint64_t error_physical_addr)
> +{
> +    GArray *block;
> +    uint64_t current_block_length;
> +    uint32_t data_length;
> +    /* Memory section */
The variable name is clear I think, so not sure this comment adds any 
information.

> +    char mem_section_id_le[] = {0x14, 0x11, 0xBC, 0xA5, 0x64, 0x6F, 0xDE,
> +                                0x4E, 0xB8, 0x63, 0x3E, 0x83, 0xED, 0x7C,
> +                                0x83, 0xB1};
> +    uint8_t fru_id[16] = {0};
> +    uint8_t fru_text[20] = {0};
> +
> +    /* Generic Error Status Block
> +     * | +---------------------+
> +     * | |     block_status    |
> +     * | +---------------------+
> +     * | |    raw_data_offset  |
> +     * | +---------------------+
> +     * | |    raw_data_length  |
> +     * | +---------------------+
> +     * | |     data_length     |
> +     * | +---------------------+
> +     * | |   error_severity    |
> +     * | +---------------------+
> +     */
> +    block = g_array_new(false, true /* clear */, 1);
> +
> +    /* Get the length of the Generic Error Data Entries */
> +    cpu_physical_memory_read(error_block_address +
> +        offsetof(AcpiGenericErrorStatus, data_length), &data_length, 4);
> +
> +    /* The current whole length of the generic error status block */
> +    current_block_length = sizeof(AcpiGenericErrorStatus) + 
> le32_to_cpu(data_length);
> +
> +    /* This is the length if adding a new generic error data entry*/
> +    data_length += GHES_DATA_LENGTH;
> +    data_length += GHES_MEM_CPER_LENGTH;
> +
> +    /* Check whether it will run out of the preallocated memory if adding a 
> new
> +     * generic error data entry
> +     */
> +    if ((data_length + sizeof(AcpiGenericErrorStatus)) > 
> GHES_MAX_RAW_DATA_LENGTH) {
> +        error_report("Record CPER out of boundary!!!");
> +        return GHES_CPER_FAIL;
> +    }
> +
> +    /* Build the new generic error status block header */
> +    build_append_ghes_generic_status(block, 
> cpu_to_le32(ACPI_GEBS_UNCORRECTABLE), 0, 0,
> +        cpu_to_le32(data_length), cpu_to_le32(ACPI_CPER_SEV_RECOVERABLE));
> +
> +    /* Write back above generic error status block header to guest memory */
> +    cpu_physical_memory_write(error_block_address, block->data,
> +                              block->len);
> +
> +    /* Add a new generic error data entry */
> +
> +    data_length = block->len;
> +    /* Build this new generic error data entry header */
> +    build_append_ghes_generic_data(block, mem_section_id_le,
> +                    cpu_to_le32(ACPI_CPER_SEV_RECOVERABLE), 
> cpu_to_le32(0x300), 0, 0,
> +                    cpu_to_le32(80)/* the total size of Memory Error Record 
> */, fru_id,

Use the define for that 80?

> +                    fru_text, 0);
> +
> +    /* Build the memory section CPER for above new generic error data entry 
> */
> +    build_append_mem_cper(block, error_physical_addr);
> +
> +    /* Write back above this new generic error data entry to guest memory */
> +    cpu_physical_memory_write(error_block_address + current_block_length,
> +                    block->data + data_length, block->len - data_length);
> +
> +    g_array_free(block, true);
> +
> +    return GHES_CPER_OK;
> +}
> +
>  /* Build table for the hardware error fw_cfg blob */
>  void build_hardware_error_table(GArray *hardware_errors, BIOSLinker *linker)
>  {
> @@ -169,3 +264,85 @@ void ghes_add_fw_cfg(FWCfgState *s, GArray 
> *hardware_error)
>      fw_cfg_add_file_callback(s, GHES_DATA_ADDR_FW_CFG_FILE, NULL, NULL, NULL,
>          &ges.ghes_addr_le, sizeof(ges.ghes_addr_le), false);
>  }
> +
> +bool ghes_record_errors(uint32_t notify, uint64_t physical_address)
> +{
> +    uint64_t error_block_addr, read_ack_register_addr;
> +    int read_ack_register = 0, loop = 0;
> +    uint64_t start_addr = le32_to_cpu(ges.ghes_addr_le);
> +    bool ret = GHES_CPER_FAIL;
> +    const uint8_t error_source_id[] = { 0xff, 0xff, 0xff, 0xff,
> +                                        0xff, 0xff, 0xff, 0, 1};
> +
> +    /*
> +     * | +---------------------+ ges.ghes_addr_le
> +     * | |error_block_address0 |
> +     * | +---------------------+ --+--
> +     * | |    .............    | GHES_ADDRESS_SIZE
> +     * | +---------------------+ --+--
> +     * | |error_block_addressN |
> +     * | +---------------------+
> +     * | | read_ack_register0  |
> +     * | +---------------------+ --+--
> +     * | |   .............     | GHES_ADDRESS_SIZE
> +     * | +---------------------+ --+--
> +     * | | read_ack_registerN  |
> +     * | +---------------------+ --+--
> +     * | |      CPER           |   |
> +     * | |      ....           | GHES_MAX_RAW_DATA_LENGT
> +     * | |      CPER           |   |
> +     * | +---------------------+ --+--
> +     * | |    ..........       |
> +     * | +---------------------+
> +     * | |      CPER           |
> +     * | |      ....           |
> +     * | |      CPER           |
> +     * | +---------------------+
> +     */
> +    if (physical_address && notify < ACPI_HEST_NOTIFY_RESERVED) {
> +        /* Find and check the source id for this new CPER */
> +        if (error_source_id[notify] != 0xff) {
> +            start_addr += error_source_id[notify] * GHES_ADDRESS_SIZE;
> +        } else {
> +            goto out;
> +        }
> +
> +        cpu_physical_memory_read(start_addr, &error_block_addr,
> +                                    GHES_ADDRESS_SIZE);
> +
> +        read_ack_register_addr = start_addr +
> +                        ACPI_HEST_ERROR_SOURCE_COUNT * GHES_ADDRESS_SIZE;
> +retry:
> +        cpu_physical_memory_read(read_ack_register_addr,
> +                                 &read_ack_register, GHES_ADDRESS_SIZE);
> +
> +        /* zero means OSPM does not acknowledge the error */
> +        if (!read_ack_register) {
> +            if (loop < 3) {
> +                usleep(100 * 1000);
> +                loop++;
> +                goto retry;
> +            } else {
> +                error_report("OSPM does not acknowledge previous error,"
> +                    " so can not record CPER for current error, forcibly 
> acknowledge"
> +                    " previous error to avoid blocking next time CPER 
> record! Exit");
> +                read_ack_register = 1;
> +                cpu_physical_memory_write(read_ack_register_addr,
> +                    &read_ack_register, GHES_ADDRESS_SIZE);
> +            }
> +        } else {
> +            if (error_block_addr) {
> +                read_ack_register = 0;
> +                /* Clear the Read Ack Register, OSPM will write it to 1 when
> +                 * acknowledge this error.
> +                 */
> +                cpu_physical_memory_write(read_ack_register_addr,
> +                    &read_ack_register, GHES_ADDRESS_SIZE);
> +                ret = ghes_record_mem_error(error_block_addr, 
> physical_address);
> +            }
> +        }
> +    }
> +
> +out:
> +    return ret;
> +}
> diff --git a/include/hw/acpi/acpi_ghes.h b/include/hw/acpi/acpi_ghes.h
> index 38fd87c..6b38097 100644
> --- a/include/hw/acpi/acpi_ghes.h
> +++ b/include/hw/acpi/acpi_ghes.h
> @@ -32,11 +32,14 @@
>  #define GHES_ADDRESS_SIZE           8
>  
>  #define GHES_DATA_LENGTH            72
> -#define GHES_CPER_LENGTH            80
> +#define GHES_MEM_CPER_LENGTH        80

This is a good change to make, but please roll it into patch 7 where
this was introduced rather than introducing it only to rename later.

Actually it would be even better to just not introduce it in patch 7
and bring it in for the first time in this patch.

>  
>  #define ReadAckPreserve             0xfffffffe
>  #define ReadAckWrite                0x1
>  
> +#define GHES_CPER_OK                1
> +#define GHES_CPER_FAIL              0
> +
>  /* The max size in bytes for one error block */
>  #define GHES_MAX_RAW_DATA_LENGTH        0x1000
>  /* Now only have GPIO-Signal and ARMv8 SEA notification types error sources
> @@ -76,4 +79,5 @@ void build_apei_hest(GArray *table_data, GArray 
> *hardware_error,
>  
>  void build_hardware_error_table(GArray *hardware_errors, BIOSLinker *linker);
>  void ghes_add_fw_cfg(FWCfgState *s, GArray *hardware_errors);
> +bool ghes_record_errors(uint32_t notify, uint64_t error_physical_addr);
>  #endif
> diff --git a/include/sysemu/kvm.h b/include/sysemu/kvm.h
> index a6d1cd1..1d1a7a8 100644
> --- a/include/sysemu/kvm.h
> +++ b/include/sysemu/kvm.h
> @@ -377,7 +377,7 @@ bool kvm_vcpu_id_is_valid(int vcpu_id);
>  /* Returns VCPU ID to be used on KVM_CREATE_VCPU ioctl() */
>  unsigned long kvm_arch_vcpu_id(CPUState *cpu);
>  
> -#ifdef TARGET_I386
> +#if defined(TARGET_I386) || defined(TARGET_AARCH64)
>  #define KVM_HAVE_MCE_INJECTION 1
>  void kvm_arch_on_sigbus_vcpu(CPUState *cpu, int code, void *addr);
>  #endif
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index c7bdc6a..d2eac28 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -27,6 +27,10 @@
>  #include "kvm_arm.h"
>  #include "internals.h"
>  #include "hw/arm/arm.h"
> +#include "exec/ram_addr.h"
> +#include "hw/acpi/acpi-defs.h"
> +#include "hw/acpi/acpi_ghes.h"
> +#include "hw/acpi/acpi.h"
>  
>  static bool have_guest_debug;
>  
> @@ -1029,6 +1033,41 @@ int kvm_arch_get_registers(CPUState *cs)
>      return ret;
>  }
>  
> +void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
> +{
> +    ram_addr_t ram_addr;
> +    hwaddr paddr;
> +
> +    assert(code == BUS_MCEERR_AR || code == BUS_MCEERR_AO);
> +
> +    if (acpi_enabled && 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)) {
> +            kvm_hwpoison_page_add(ram_addr);
> +            /* Asynchronous signal will be masked by main thread, so
> +             * only handle synchronous signal.
> +             */
> +            if (code == BUS_MCEERR_AR) {
> +                kvm_cpu_synchronize_state(c);
> +                if (GHES_CPER_FAIL != 
> ghes_record_errors(ACPI_HEST_NOTIFY_SEA, paddr)) {
> +                    kvm_inject_arm_sea(c);
> +                } else {
> +                    fprintf(stderr, "failed to record the error\n");
> +                }
> +            }
> +            return;
> +        }
> +        fprintf(stderr, "Hardware memory error for memory used by "
> +                "QEMU itself instead of guest system!\n");
> +    }
> +
> +    if (code == BUS_MCEERR_AR) {
> +        fprintf(stderr, "Hardware memory error!\n");
> +        exit(1);
> +    }
> +}
> +
>  /* C6.6.29 BRK instruction */
>  static const uint32_t brk_insn = 0xd4200000;
>