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

From: Gavin Shan <[email-masked]>
Date: Tue, 24 Mar 2015 09:47:54 +1100

On Mon, Mar 23, 2015 at 10:14:59AM -0600, Alex Williamson wrote:
>On Mon, 2015-03-23 at 16:20 +1100, Gavin Shan wrote:
>> On Mon, Mar 23, 2015 at 04:10:20PM +1100, David Gibson wrote:
>> >On Mon, Mar 23, 2015 at 04:03:59PM +1100, Gavin Shan wrote:
>> >> 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 <[email-masked]>
>> >> >> >
>> >> >> >Reviewed-by: David Gibson <[email-masked]>
>> >> >> >
>> >> >> >> ---
>> >> >> >>  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
>> >
>> >Oh.. I see your point.
>> >
>> >Yes, the EEH internal code shouldn't need to use the VFIO defined
>> >constants.
>> >
>> >But it's still silly to duplicate, I think the correct think would be
>> >to expose the EEH constants in uapi, and use those for VFIO as well.
>> >
>> 
>> I'm not sure. If Alex.W agree on this, I can have one patch to address
>> it in future :-)
>
>I agree with David, there should be a uapi eeh header and the vfio
>documentation should define that as the valid set of functions.
>
>> >> - 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.
>> >
>> >But is there any reason not to make them stable.  The VFIO case shows
>> >that we need to lock down an interface somewhere.  I don't see that
>> >there's an advantage to having a not locked down interface in addition
>> >to a locked down one.
>> >
>> 
>> I was saying that the UAPI interace should be stable. I don't see
>> there're any reasons the UAPI interface will be changed in near
>> future :)
>
>When I asked previously whether a translation layer was needed between
>the vfio uapi and kernel internal eeh api I was told that the values
>were defined by the spapr spec and therefore not changeable.  If that's
>true, we shouldn't need to worry about exporting them via uapi.  Thanks,
>

Well. It sounds a good idea. I'll add one separate patch, which would be
PATCH[3/3] in next revision to address it. Currently, there are not
too much constants, which can be put into arch/powerpc/include/uapi/asm/eeh.h.
The following list are the candidates from include/api/vfio.h, which can be
moved to uapi/asm/eeh.h. The names of those constants will be changed from
"VFIO_EEH_*" to "EEH_*" and then user space will have some code as folows
to use them. That looks a bit weird. Do we really want moving those constants
to uapi/asm/eeh.h and rename them accordingly?

#include <stdio.h>
#include <sys/ioctl.h>
#include <eeh.h>
#include <vfio.h>

struct vfio_eeh_pe_op pe_op = { .argsz = sizeof(pe_op), .flags = 0 };

pe_op.op = VFIO_EEH_PE_INJECT_ERR;		/* Its prefix is  "VFIO_EEH_* */
pe_op.err.type = EEH_ERR_TYPE_32;		/* It starts with "EEH_*"     */
pe_op.err.func = EEH_ERR_FUNC_LD_CFG_ADDR;
pe_op.err.addr = 0ul;
pe_op.err.mask = 0ul;
ioctl(container, VFIO_EEH_PE_OP, &pe_op);

---

#define  VFIO_EEH_PE_STATE_NORMAL       0       /* PE in functional state    */
#define  VFIO_EEH_PE_STATE_RESET        1       /* PE reset in progress      */
#define  VFIO_EEH_PE_STATE_STOPPED      2       /* Stopped DMA and IO        */
#define  VFIO_EEH_PE_STATE_STOPPED_DMA  4       /* Stopped DMA only          */
#define  VFIO_EEH_PE_STATE_UNAVAIL      5       /* State unavailable         */

#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

Thanks,
Gavin

>Alex
>
>> >> - 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
>> 
>> 
>
>
>
>_______________________________________________
>Linuxppc-dev mailing list
>[email-masked]
>https://lists.ozlabs.org/listinfo/linuxppc-dev