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Subject[PATCH v4 3/5] vfio: type1: replace domain wide protection flags with supported capabilities
Date
From: Antonios Motakis <a.motakis@virtualopensystems.com>

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@virtualopensystems.com>
[Baptiste Reynal: Use bit shifting for domain->caps]
Signed-off-by: Baptiste Reynal <b.reynal@virtualopensystems.com>
---
drivers/vfio/vfio_iommu_type1.c | 31 ++++++++++++++++++++++---------
1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 57d8c37..998619b 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;
bool fgsp; /* Fine-grained super pages */
};

@@ -507,7 +507,7 @@ 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;
}
@@ -525,11 +525,16 @@ 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 & (1 << 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;
}

@@ -644,6 +649,10 @@ 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 & (1 << 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);
@@ -677,7 +686,7 @@ 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;

@@ -702,13 +711,17 @@ static void vfio_test_domain_fgsp(struct vfio_domain *domain)
{
struct page *pages;
int ret, order = get_order(PAGE_SIZE * 2);
+ int dprot = 0;
+
+ if (domain->caps & (1 << IOMMU_CAP_CACHE_COHERENCY))
+ dprot |= IOMMU_CACHE;

pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
if (!pages)
return;

ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
- IOMMU_READ | IOMMU_WRITE | domain->prot);
+ IOMMU_READ | IOMMU_WRITE | dprot);
if (!ret) {
size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);

@@ -787,7 +800,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
}

if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
- domain->prot |= IOMMU_CACHE;
+ domain->caps |= (1 << IOMMU_CAP_CACHE_COHERENCY);

/*
* Try to match an existing compatible domain. We don't want to
@@ -798,7 +811,7 @@ 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);
@@ -942,7 +955,7 @@ 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;
}
--
2.3.1


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