* [PATCH v3 4/6] vfio: type1: replace domain wide protection flags with supported capabilities
@ 2015-01-29 12:24 GAUGUEY Rémy 228890
[not found] ` <022C7612790E20489F80A6F0D54B849F3B2C11AD-C/8XDKI8rPk8KqdCPk9DGyghONGMnRii@public.gmane.org>
0 siblings, 1 reply; 3+ messages in thread
From: GAUGUEY Rémy 228890 @ 2015-01-29 12:24 UTC (permalink / raw)
To: Antonios Motakis, kvmarm@lists.cs.columbia.edu,
iommu@lists.linux-foundation.org, alex.williamson@redhat.com
Cc: open list:VFIO DRIVER, will.deacon@arm.com, open list,
tech@virtualopensystems.com
Hi Antonios,
On Thu, 27 Nov 2014 18:22:53 Antonios Motakis wrote:
>VFIO_IOMMU_TYPE1 keeps track for each domain it knows a list of protection
>flags it always applies to all mappings in the domain. This is used for
>domains that support IOMMU_CAP_CACHE_COHERENCY.
>
>Refactor this slightly, by keeping track instead that a given domain
>supports the capability, and applying the IOMMU_CACHE protection flag when
>doing the actual DMA mappings.
>
>This will allow us to reuse the behavior for IOMMU_CAP_NOEXEC, which we
>also want to keep track of, but without applying it to all domains that
>support it unless the user explicitly requests it.
>
>Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
>---
> drivers/vfio/vfio_iommu_type1.c | 25 +++++++++++++++++--------
> 1 file changed, 17 insertions(+), 8 deletions(-)
>
>diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
>index 4a9d666..c54dab8 100644
>--- a/drivers/vfio/vfio_iommu_type1.c
>+++ b/drivers/vfio/vfio_iommu_type1.c
> if (ret)
> return ret;
>
>@@ -731,7 +740,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
> }
>
> if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
>- domain->prot |= IOMMU_CACHE;
>+ domain->caps |= IOMMU_CAP_CACHE_COHERENCY;
IMHO this is not good since IOMMU_CAP_CACHE_COHERENCY is not a bitfield but an enum
See include/linux/iommu.h
enum iommu_cap {
IOMMU_CAP_CACHE_COHERENCY, /* IOMMU can enforce cache coherent DMA
transactions */
IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */
};
One possible fix would to redefine the enum with values with bitfiled values
enum iommu_cap {
IOMMU_CAP_CACHE_COHERENCY = 1, /* IOMMU can enforce cache coherent DMA
transactions */
IOMMU_CAP_INTR_REMAP = 2, /* IOMMU supports interrupt isolation */
IOMMU_CAP_NOEXEC = 4, /* IOMMU_NOEXEC flag */
};
Regards
Rémy
>_______________________________________________
>kvmarm mailing list
>kvmarm@xxxxxxxxxxxxxxxxxxxxx
https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
^ permalink raw reply [flat|nested] 3+ messages in thread[parent not found: <022C7612790E20489F80A6F0D54B849F3B2C11AD-C/8XDKI8rPk8KqdCPk9DGyghONGMnRii@public.gmane.org>]
* Re: [PATCH v3 4/6] vfio: type1: replace domain wide protection flags with supported capabilities [not found] ` <022C7612790E20489F80A6F0D54B849F3B2C11AD-C/8XDKI8rPk8KqdCPk9DGyghONGMnRii@public.gmane.org> @ 2015-01-29 16:13 ` Alex Williamson 0 siblings, 0 replies; 3+ messages in thread From: Alex Williamson @ 2015-01-29 16:13 UTC (permalink / raw) To: GAUGUEY Rémy 228890 Cc: open list:VFIO DRIVER, will.deacon-5wv7dgnIgG8@public.gmane.org, open list, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, Antonios Motakis, tech-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org, kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg@public.gmane.org On Thu, 2015-01-29 at 12:24 +0000, GAUGUEY Rémy 228890 wrote: > Hi Antonios, > > On Thu, 27 Nov 2014 18:22:53 Antonios Motakis wrote: > >VFIO_IOMMU_TYPE1 keeps track for each domain it knows a list of protection > >flags it always applies to all mappings in the domain. This is used for > >domains that support IOMMU_CAP_CACHE_COHERENCY. > > > >Refactor this slightly, by keeping track instead that a given domain > >supports the capability, and applying the IOMMU_CACHE protection flag when > >doing the actual DMA mappings. > > > >This will allow us to reuse the behavior for IOMMU_CAP_NOEXEC, which we > >also want to keep track of, but without applying it to all domains that > >support it unless the user explicitly requests it. > > > >Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx> > >--- > > drivers/vfio/vfio_iommu_type1.c | 25 +++++++++++++++++-------- > > 1 file changed, 17 insertions(+), 8 deletions(-) > > > >diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c > >index 4a9d666..c54dab8 100644 > >--- a/drivers/vfio/vfio_iommu_type1.c > >+++ b/drivers/vfio/vfio_iommu_type1.c > > if (ret) > > return ret; > > > >@@ -731,7 +740,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, > > } > > > > if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY)) > >- domain->prot |= IOMMU_CACHE; > >+ domain->caps |= IOMMU_CAP_CACHE_COHERENCY; > > IMHO this is not good since IOMMU_CAP_CACHE_COHERENCY is not a bitfield but an enum > See include/linux/iommu.h > enum iommu_cap { > IOMMU_CAP_CACHE_COHERENCY, /* IOMMU can enforce cache coherent DMA > transactions */ > IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ > }; Good catch! > One possible fix would to redefine the enum with values with bitfiled values > enum iommu_cap { > IOMMU_CAP_CACHE_COHERENCY = 1, /* IOMMU can enforce cache coherent DMA > transactions */ > IOMMU_CAP_INTR_REMAP = 2, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC = 4, /* IOMMU_NOEXEC flag */ > }; This seems like a large imposition on the IOMMU code to conform to our specific use case. Perhaps the method used by the original code to cache domain overriding mapping flags separately is the better approach. Thanks, Alex _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu ^ permalink raw reply [flat|nested] 3+ messages in thread
[parent not found: <1417108976-10113-1-git-send-email-a.motakis@virtualopensystems.com>]
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* [PATCH v3 4/6] vfio: type1: replace domain wide protection flags with supported capabilities [not found] ` <1417108976-10113-1-git-send-email-a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org> @ 2014-11-27 17:22 ` Antonios Motakis 0 siblings, 0 replies; 3+ messages in thread From: Antonios Motakis @ 2014-11-27 17:22 UTC (permalink / raw) To: kvmarm-FPEHb7Xf0XXUo1n7N8X6UoWGPAHP3yOg, iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA, alex.williamson-H+wXaHxf7aLQT0dZR+AlfA Cc: open list:VFIO DRIVER, eric.auger-QSEj5FYQhm4dnm+yROfE0A, marc.zyngier-5wv7dgnIgG8, will.deacon-5wv7dgnIgG8, open list, Antonios Motakis, tech-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J, christoffer.dall-QSEj5FYQhm4dnm+yROfE0A VFIO_IOMMU_TYPE1 keeps track for each domain it knows a list of protection flags it always applies to all mappings in the domain. This is used for domains that support IOMMU_CAP_CACHE_COHERENCY. Refactor this slightly, by keeping track instead that a given domain supports the capability, and applying the IOMMU_CACHE protection flag when doing the actual DMA mappings. This will allow us to reuse the behavior for IOMMU_CAP_NOEXEC, which we also want to keep track of, but without applying it to all domains that support it unless the user explicitly requests it. Signed-off-by: Antonios Motakis <a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org> --- drivers/vfio/vfio_iommu_type1.c | 25 +++++++++++++++++-------- 1 file changed, 17 insertions(+), 8 deletions(-) diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c index 4a9d666..c54dab8 100644 --- a/drivers/vfio/vfio_iommu_type1.c +++ b/drivers/vfio/vfio_iommu_type1.c @@ -65,7 +65,7 @@ struct vfio_domain { struct iommu_domain *domain; struct list_head next; struct list_head group_list; - int prot; /* IOMMU_CACHE */ + int caps; }; struct vfio_dma { @@ -486,7 +486,7 @@ static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova, for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) { ret = iommu_map(domain->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT, - PAGE_SIZE, prot | domain->prot); + PAGE_SIZE, prot); if (ret) break; } @@ -504,11 +504,16 @@ static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova, int ret; list_for_each_entry(d, &iommu->domain_list, next) { + int dprot = prot; + + if (d->caps & IOMMU_CAP_CACHE_COHERENCY) + dprot |= IOMMU_CACHE; + ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT, - npage << PAGE_SHIFT, prot | d->prot); + npage << PAGE_SHIFT, dprot); if (ret) { if (ret != -EBUSY || - map_try_harder(d, iova, pfn, npage, prot)) + map_try_harder(d, iova, pfn, npage, dprot)) goto unwind; } } @@ -621,6 +626,10 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, struct vfio_domain *d; struct rb_node *n; int ret; + int dprot = 0; + + if (domain->caps & IOMMU_CAP_CACHE_COHERENCY) + dprot |= IOMMU_CACHE; /* Arbitrarily pick the first domain in the list for lookups */ d = list_first_entry(&iommu->domain_list, struct vfio_domain, next); @@ -654,7 +663,7 @@ static int vfio_iommu_replay(struct vfio_iommu *iommu, size += PAGE_SIZE; ret = iommu_map(domain->domain, iova, phys, - size, dma->prot | domain->prot); + size, dma->prot | dprot); if (ret) return ret; @@ -731,7 +740,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, } if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY)) - domain->prot |= IOMMU_CACHE; + domain->caps |= IOMMU_CAP_CACHE_COHERENCY; /* * Try to match an existing compatible domain. We don't want to @@ -742,7 +751,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data, */ list_for_each_entry(d, &iommu->domain_list, next) { if (d->domain->ops == domain->domain->ops && - d->prot == domain->prot) { + d->caps == domain->caps) { iommu_detach_group(domain->domain, iommu_group); if (!iommu_attach_group(d->domain, iommu_group)) { list_add(&group->next, &d->group_list); @@ -884,7 +893,7 @@ static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu) mutex_lock(&iommu->lock); list_for_each_entry(domain, &iommu->domain_list, next) { - if (!(domain->prot & IOMMU_CACHE)) { + if (!(domain->caps & IOMMU_CAP_CACHE_COHERENCY)) { ret = 0; break; } -- 2.1.3 ^ permalink raw reply related [flat|nested] 3+ messages in thread
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2015-01-29 12:24 [PATCH v3 4/6] vfio: type1: replace domain wide protection flags with supported capabilities GAUGUEY Rémy 228890
[not found] ` <022C7612790E20489F80A6F0D54B849F3B2C11AD-C/8XDKI8rPk8KqdCPk9DGyghONGMnRii@public.gmane.org>
2015-01-29 16:13 ` Alex Williamson
[not found] <1417108976-10113-1-git-send-email-a.motakis@virtualopensystems.com>
[not found] ` <1417108976-10113-1-git-send-email-a.motakis-lrHrjnjw1UfHK3s98zE1ajGjJy/sRE9J@public.gmane.org>
2014-11-27 17:22 ` Antonios Motakis
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