Re: [Qemu-devel] [PATCH v2 3/4] target-ppc: Build error log

[Alexey Kardashevskiy <aik@au1.ibm.com>]

On 09/04/2014 09:13 PM, Aravinda Prasad wrote:
> Whenever there is a physical memory error due to bit
> flips, which cannot be corrected by hardware, the error
> is passed on to the kernel. If the memory address in
> error belongs to guest address space then guest kernel
> is responsible to take action. Hence the error is passed
> on to guest via KVM by invoking 0x200 NMI vector.
> 
> However, guest OS, as per PAPR, expects an error log
> upon such error. This patch registers a new hcall
> which is issued from 0x200 interrupt vector and builds
> the error log, copies the error log to rtas space and
> passes the address of the error log to guest
> 
> Enhancement to KVM to perform above functionality is
> already in upstream kernel.
> 
> Signed-off-by: Aravinda Prasad <aravinda@linux.vnet.ibm.com>
> ---
>  hw/ppc/spapr_hcall.c   |  154 ++++++++++++++++++++++++++++++++++++++++++++++++
>  include/hw/ppc/spapr.h |    4 +
>  2 files changed, 157 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/ppc/spapr_hcall.c b/hw/ppc/spapr_hcall.c
> index 01650ba..c3aa448 100644
> --- a/hw/ppc/spapr_hcall.c
> +++ b/hw/ppc/spapr_hcall.c
> @@ -14,6 +14,88 @@ struct SPRSyncState {
>      target_ulong mask;
>  };
>  
> +/* Offset from rtas-base where error log is placed */
> +#define RTAS_ERROR_OFFSET       (TARGET_PAGE_SIZE)
> +
> +#define RTAS_ELOG_SEVERITY_SHIFT         0x5
> +#define RTAS_ELOG_DISPOSITION_SHIFT      0x3
> +#define RTAS_ELOG_INITIATOR_SHIFT        0x4
> +
> +/*
> + * Only required RTAS event severity, disposition, initiator
> + * target and type are copied from arch/powerpc/include/asm/rtas.h
> + */
> +
> +/* RTAS event severity */
> +#define RTAS_SEVERITY_ERROR_SYNC    0x3
> +
> +/* RTAS event disposition */
> +#define RTAS_DISP_NOT_RECOVERED     0x2
> +
> +/* RTAS event initiator */
> +#define RTAS_INITIATOR_MEMORY       0x4
> +
> +/* RTAS event target */
> +#define RTAS_TARGET_MEMORY          0x4
> +
> +/* RTAS event type */
> +#define RTAS_TYPE_ECC_UNCORR        0x09
> +
> +/*
> + * Currently KVM only passes on the uncorrected machine
> + * check memory error to guest. Other machine check errors
> + * such as SLB multi-hit and TLB multi-hit are recovered
> + * in KVM and are not passed on to guest.
> + *
> + * DSISR Bit for uncorrected machine check error. Based
> + * on arch/powerpc/include/asm/mce.h
> + */
> +#define PPC_BIT(bit)                (0x8000000000000000ULL >> bit)
> +#define P7_DSISR_MC_UE              (PPC_BIT(48))  /* P8 too */
> +
> +/* Adopted from kernel source arch/powerpc/include/asm/rtas.h */
> +struct rtas_error_log {
> +    /* Byte 0 */
> +    uint8_t     byte0;          /* Architectural version */
> +
> +    /* Byte 1 */
> +    uint8_t     byte1;
> +    /* XXXXXXXX
> +     * XXX      3: Severity level of error
> +     *    XX    2: Degree of recovery
> +     *      X   1: Extended log present?
> +     *       XX 2: Reserved
> +     */
> +
> +    /* Byte 2 */
> +    uint8_t     byte2;
> +    /* XXXXXXXX
> +     * XXXX     4: Initiator of event
> +     *     XXXX 4: Target of failed operation
> +     */
> +    uint8_t     byte3;          /* General event or error*/
> +};


Any particular reason not to copy rtas_error_log as is?




-- 
Alexey Kardashevskiy
IBM OzLabs, LTC Team

e-mail: aik@au1.ibm.com
notes: Alexey Kardashevskiy/Australia/IBM