Hi Cédric,
Thanks for taking a look at this patch. Please find my responses below:
On 2025/04/08 08:29 AM, Cédric Le Goater wrote:
> Hello Amit,
>
> Please use --cover-letter for the next spin.
Sure, will do.
>
>
> On 4/7/25 16:31, Amit Machhiwal wrote:
> > Introduce an Error ** parameter to vfio_spapr_create_window() to enable
> > structured error reporting. This allows the function to propagate
> > detailed errors back to callers.
> >
> > Suggested-by: Cédric Le Goater <c...@redhat.com>
> > Signed-off-by: Amit Machhiwal <amach...@linux.ibm.com>
> > ---
> > hw/vfio/spapr.c | 23 ++++++++++++-----------
> > 1 file changed, 12 insertions(+), 11 deletions(-)
> >
> > diff --git a/hw/vfio/spapr.c b/hw/vfio/spapr.c
> > index 1a5d1611f2cd..4f2858b43f36 100644
> > --- a/hw/vfio/spapr.c
> > +++ b/hw/vfio/spapr.c
> > @@ -232,7 +232,7 @@ static int vfio_spapr_remove_window(VFIOContainer
> > *container,
> > static int vfio_spapr_create_window(VFIOContainer *container,
>
> This routine can return a bool since vfio_spapr_container_add_section_window()
> does not check the returned errno.
Sure, I can make this change in next version.
>
> > MemoryRegionSection *section,
> > - hwaddr *pgsize)
> > + hwaddr *pgsize, Error **errp)
> > {
> > int ret = 0;
> > VFIOContainerBase *bcontainer = &container->bcontainer;
> > @@ -252,10 +252,10 @@ static int vfio_spapr_create_window(VFIOContainer
> > *container,
> > pgmask = bcontainer->pgsizes & (pagesize | (pagesize - 1));
> > pagesize = pgmask ? (1ULL << (63 - clz64(pgmask))) : 0;
> > if (!pagesize) {
> > - error_report("Host doesn't support page size 0x%"PRIx64
> > - ", the supported mask is 0x%lx",
> > - memory_region_iommu_get_min_page_size(iommu_mr),
> > - bcontainer->pgsizes);
> > + error_setg(errp, "Host doesn't support page size 0x%"PRIx64
> > + ", the supported mask is 0x%lx",
> > + memory_region_iommu_get_min_page_size(iommu_mr),
> > + bcontainer->pgsizes);
>
> This can use error_setg_errno(errp, EINVAL, ... ) instead of
> returning -EINVAL.
Sure.
>
> > return -EINVAL;
> > }
> > @@ -302,16 +302,16 @@ static int vfio_spapr_create_window(VFIOContainer
> > *container,
> > }
> > }
> > if (ret) {
> > - error_report("Failed to create a window, ret = %d (%m)", ret);
> > + error_setg_errno(errp, -ret, "Failed to create a window, ret = %d
> > (%m)", ret);
> > return -errno;
> > }
> > if (create.start_addr != section->offset_within_address_space) {
> > vfio_spapr_remove_window(container, create.start_addr);
> > - error_report("Host doesn't support DMA window at %"HWADDR_PRIx",
> > must be %"PRIx64,
> > - section->offset_within_address_space,
> > - (uint64_t)create.start_addr);
> > + error_setg(errp, "Host doesn't support DMA window at %"HWADDR_PRIx
> > + ", must be %"PRIx64,
> > section->offset_within_address_space,
> > + (uint64_t)create.start_addr);
>
> This can use error_setg_errno(errp, EINVAL, ... ) instead of
> returning -EINVAL.
Sure.
>
> > return -EINVAL;
> > }
> > trace_vfio_spapr_create_window(create.page_shift,
> > @@ -334,6 +334,7 @@
> > vfio_spapr_container_add_section_window(VFIOContainerBase *bcontainer,
> > container);
> > VFIOHostDMAWindow *hostwin;
> > hwaddr pgsize = 0;
> > + Error *local_err = NULL;
> > int ret;> /*
> > @@ -377,9 +378,9 @@
> > vfio_spapr_container_add_section_window(VFIOContainerBase *bcontainer,
> > }
> > }
> > - ret = vfio_spapr_create_window(container, section, &pgsize);
> > + ret = vfio_spapr_create_window(container, section, &pgsize,
> > &local_err);
>
> please pass errp instead.
>
> > if (ret) {
> > - error_setg_errno(errp, -ret, "Failed to create SPAPR window");
> > + error_propagate(errp, local_err);
>
> no need to propagate if errp is passed to vfio_spapr_create_window()
As per my understanding, for calling error_setg() and friends, the Error **
object has be NULL. If I were to call vfio_spapr_create_window() with errp
instead of the local Error object, that'd result into the below assertion
failure with only the first patch applied and a guest booted with a memory >
128G and PCI device passthrough:
qemu-system-ppc64: ../util/error.c:68: error_setv: Assertion `*errp == NULL'
failed.
This happens because the errp would already be set in vfio_spapr_create_window()
and calling error_setg_errno(errp, ...) in
vfio_spapr_container_add_section_window()
would fail as errp is no more NULL. This is the reason I chose to use a local
Error object and later propagate it with errp.
IIUC, what you mean is to pass errp in vfio_spapr_create_window() and just
return from this condition in vfio_spapr_container_add_section_window() but no
need to call error_setg_errno() or error_propagate(). I think that would work.
Please correct me.
Thanks,
Amit
>
>
> Thanks,
>
> C.
>
>
> > return false;
> > }
> >
> > base-commit: 53f3a13ac1069975ad47cf8bd05cc96b4ac09962
>
