Re: [PATCH v3 2/2] drivers/vfio: Support EEH error injection

Gavin Shan
2015-03-23T05:05:03Z

On Mon, Mar 23, 2015 at 02:43:03PM +1100, David Gibson wrote:
>On Mon, Mar 23, 2015 at 12:56:36PM +1100, Gavin Shan wrote:
>> On Mon, Mar 23, 2015 at 12:39:45PM +1100, David Gibson wrote:
>> >On Sat, Mar 21, 2015 at 06:58:45AM +1100, Gavin Shan wrote:
>> >> The patch adds one more EEH sub-command (VFIO_EEH_PE_INJECT_ERR)
>> >> to inject the specified EEH error, which is represented by
>> >> (struct vfio_eeh_pe_err), to the indicated PE for testing purpose.
>> >>
>> >> Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
>> >
>> >Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
>> >
>> >> ---
>> >> Documentation/vfio.txt | 12 ++++++++++++
>> >> drivers/vfio/vfio_spapr_eeh.c | 10 ++++++++++
>> >> include/uapi/linux/vfio.h | 36 +++++++++++++++++++++++++++++++++++-
>> >> 3 files changed, 57 insertions(+), 1 deletion(-)
>> >>
>> >> diff --git a/Documentation/vfio.txt b/Documentation/vfio.txt
>> >> index 96978ec..c6e11a3 100644
>> >> --- a/Documentation/vfio.txt
>> >> +++ b/Documentation/vfio.txt
>> >> @@ -385,6 +385,18 @@ The code flow from the example above should be slightly changed:
>> >>
>> >> ....
>> >>
>> >> + /* Inject EEH error, which is expected to be caused by 32-bits
>> >> + * config load.
>> >> + */
>> >> + pe_op.op = VFIO_EEH_PE_INJECT_ERR;
>> >> + pe_op.err.type = VFIO_EEH_ERR_TYPE_32;
>> >> + pe_op.err.func = VFIO_EEH_ERR_FUNC_LD_CFG_ADDR;
>> >> + pe_op.err.addr = 0ul;
>> >> + pe_op.err.mask = 0ul;
>> >> + ioctl(container, VFIO_EEH_PE_OP, &pe_op);
>> >> +
>> >> + ....
>> >> +
>> >> /* When 0xFF's returned from reading PCI config space or IO BARs
>> >> * of the PCI device. Check the PE's state to see if that has been
>> >> * frozen.
>> >> diff --git a/drivers/vfio/vfio_spapr_eeh.c b/drivers/vfio/vfio_spapr_eeh.c
>> >> index 5fa42db..38edeb4 100644
>> >> --- a/drivers/vfio/vfio_spapr_eeh.c
>> >> +++ b/drivers/vfio/vfio_spapr_eeh.c
>> >> @@ -85,6 +85,16 @@ long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
>> >> case VFIO_EEH_PE_CONFIGURE:
>> >> ret = eeh_pe_configure(pe);
>> >> break;
>> >> + case VFIO_EEH_PE_INJECT_ERR:
>> >> + minsz = offsetofend(struct vfio_eeh_pe_op, err.mask);
>> >> + if (op.argsz < minsz)
>> >> + return -EINVAL;
>> >> + if (copy_from_user(&op, (void __user *)arg, minsz))
>> >> + return -EFAULT;
>> >> +
>> >> + ret = eeh_pe_inject_err(pe, op.err.type, op.err.func,
>> >> + op.err.addr, op.err.mask);
>> >> + break;
>> >> default:
>> >> ret = -EINVAL;
>> >> }
>> >> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
>> >> index 82889c3..f68e962 100644
>> >> --- a/include/uapi/linux/vfio.h
>> >> +++ b/include/uapi/linux/vfio.h
>> >> @@ -468,12 +468,23 @@ struct vfio_iommu_spapr_tce_info {
>> >> * - unfreeze IO/DMA for frozen PE;
>> >> * - read PE state;
>> >> * - reset PE;
>> >> - * - configure PE.
>> >> + * - configure PE;
>> >> + * - inject EEH error.
>> >> */
>> >> +struct vfio_eeh_pe_err {
>> >> + __u32 type;
>> >> + __u32 func;
>> >> + __u64 addr;
>> >> + __u64 mask;
>> >> +};
>> >> +
>> >> struct vfio_eeh_pe_op {
>> >> __u32 argsz;
>> >> __u32 flags;
>> >> __u32 op;
>> >> + union {
>> >> + struct vfio_eeh_pe_err err;
>> >> + };
>> >> };
>> >>
>> >> #define VFIO_EEH_PE_DISABLE 0 /* Disable EEH functionality */
>> >> @@ -490,6 +501,29 @@ struct vfio_eeh_pe_op {
>> >> #define VFIO_EEH_PE_RESET_HOT 6 /* Assert hot reset */
>> >> #define VFIO_EEH_PE_RESET_FUNDAMENTAL 7 /* Assert fundamental reset */
>> >> #define VFIO_EEH_PE_CONFIGURE 8 /* PE configuration */
>> >> +#define VFIO_EEH_PE_INJECT_ERR 9 /* Inject EEH error */
>> >> +#define VFIO_EEH_ERR_TYPE_32 0 /* 32-bits EEH error type */
>> >> +#define VFIO_EEH_ERR_TYPE_64 1 /* 64-bits EEH error type */
>> >> +#define VFIO_EEH_ERR_FUNC_LD_MEM_ADDR 0 /* Memory load */
>> >> +#define VFIO_EEH_ERR_FUNC_LD_MEM_DATA 1
>> >> +#define VFIO_EEH_ERR_FUNC_LD_IO_ADDR 2 /* IO load */
>> >> +#define VFIO_EEH_ERR_FUNC_LD_IO_DATA 3
>> >> +#define VFIO_EEH_ERR_FUNC_LD_CFG_ADDR 4 /* Config load */
>> >> +#define VFIO_EEH_ERR_FUNC_LD_CFG_DATA 5
>> >> +#define VFIO_EEH_ERR_FUNC_ST_MEM_ADDR 6 /* Memory store */
>> >> +#define VFIO_EEH_ERR_FUNC_ST_MEM_DATA 7
>> >> +#define VFIO_EEH_ERR_FUNC_ST_IO_ADDR 8 /* IO store */
>> >> +#define VFIO_EEH_ERR_FUNC_ST_IO_DATA 9
>> >> +#define VFIO_EEH_ERR_FUNC_ST_CFG_ADDR 10 /* Config store */
>> >> +#define VFIO_EEH_ERR_FUNC_ST_CFG_DATA 11
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_RD_ADDR 12 /* DMA read */
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_RD_DATA 13
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_RD_MASTER 14
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_RD_TARGET 15
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_WR_ADDR 16 /* DMA write */
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_WR_DATA 17
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_WR_MASTER 18
>> >> +#define VFIO_EEH_ERR_FUNC_DMA_WR_TARGET 19
>> >
>> >These all seem to duplicate (under slightly different names) the
>> >defines you just added in arch/powerpc/include/asm/eeh.h. It would
>> >make more sense to only have the uapi copy, surely.
>> >
>>
>> David, Thanks for your time. The defines in eeh.h is used not only
>> for mapping those constants defined in vfio.h, but also for validating
>> arguments from debugfs entry "err_injct". So it'd better to keep
>> them separate: one set is used by userspace, another set is used
>> by host kernel.
>
>I don't understand why this is an argument for duplicating them. They
>have the same meanings and values, why can't you use the uapi versions
>everywhere?
>

We can drop the constants defined in eeh.h and just use those defines
in vfio.h. But I prefer separate constants for some ovbious reasons
except the one I mentioned above :)

- We already had separate sets of constants for EEH and VFIO. For example,
VFIO_EEH_PE_STATE_* in include/uapi/vfio.h always have counter part in
arch/powerpc/asm/include/eeh.h
- The UAPI interface is expected to be stable, or back-compatible when
introducing changes to it. The defines (at least their names) in eeh.h
doesn't have to be stable.
- I would like keep the code between EEH/VFIO independent to each other
enough.

Thanks,
Gavin

>> By the way, Alex Williamson, could you please ACK this if you don't
>> find obvious errors in the patch. I really want this to be merged
>> to 4.1.
>>
>> Thanks,
>> Gavin
>>
>>
>>
>
>--
>David Gibson | I'll have my music baroque, and my code
>david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
> | _way_ _around_!
>http://www.ozlabs.org/~dgibson