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

[gengdongjiu <gengdongjiu@huawei.com>]

> 
> On Tue, 14 May 2019 04:18:23 -0700
> Dongjiu Geng <gengdongjiu@huawei.com> 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 <james.morse@arm.com>
> > Signed-off-by: Dongjiu Geng <gengdongjiu@huawei.com>
> Hi Dongjiu,
> 
> Good to see this moving forwards again.
> 
> A few really minor things inline.

Jonathan,
   It is good to see your comments, thanks for the review.

> 
> 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.

Ok, it is good to have such a comment, I will add it.

> 
> 
> > +    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.

Ok

> 
> > +}
> > +
> > +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.

Ok, I will remove this comment since the variable name can tell the meaning.

> 
> > +    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?

Ok, I will.

> 
> > +                    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.

Yes, you are right, I will do it. 

> 
> >
> >  #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;
> >
>