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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [PATCH v10 6/7] vtd: use a bit field for context_entry
From: Paul Durrant <pdurrant@xxxxxxxxxx>
This removes the need for much shifting, masking and several magic numbers.
On the whole it makes the code quite a bit more readable.
Signed-off-by: Paul Durrant <pdurrant@xxxxxxxxxx>
---
Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
v10:
- Remove macros in favour of direct field access
- Adjust field types
- Add missing barriers
v4:
- New in v4
---
xen/drivers/passthrough/vtd/iommu.c | 36 +++++++++++----------
xen/drivers/passthrough/vtd/iommu.h | 45 +++++++++++++--------------
xen/drivers/passthrough/vtd/utils.c | 10 +++---
xen/drivers/passthrough/vtd/x86/ats.c | 6 ++--
4 files changed, 47 insertions(+), 50 deletions(-)
diff --git a/xen/drivers/passthrough/vtd/iommu.c
b/xen/drivers/passthrough/vtd/iommu.c
index 1a038541f0a3..fdb472ad6515 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -86,8 +86,6 @@ static int domain_iommu_domid(struct domain *d,
return -1;
}
-#define DID_FIELD_WIDTH 16
-#define DID_HIGH_OFFSET 8
static int context_set_domain_id(struct context_entry *context,
struct domain *d,
struct vtd_iommu *iommu)
@@ -121,21 +119,22 @@ static int context_set_domain_id(struct context_entry
*context,
}
set_bit(i, iommu->domid_bitmap);
- context->hi |= (i & ((1 << DID_FIELD_WIDTH) - 1)) << DID_HIGH_OFFSET;
+ context->did = i;
+
return 0;
}
static int context_get_domain_id(struct context_entry *context,
struct vtd_iommu *iommu)
{
- unsigned long dom_index, nr_dom;
int domid = -1;
if (iommu && context)
{
- nr_dom = cap_ndoms(iommu->cap);
+ unsigned long dom_index, nr_dom;
- dom_index = context_domain_id(*context);
+ nr_dom = cap_ndoms(iommu->cap);
+ dom_index = context->did;
if ( dom_index < nr_dom && iommu->domid_map )
domid = iommu->domid_map[dom_index];
@@ -1338,7 +1337,7 @@ int domain_context_mapping_one(
context_entries = (struct context_entry *)map_vtd_domain_page(maddr);
context = &context_entries[devfn];
- if ( context_present(*context) )
+ if ( context->p )
{
int res = 0;
@@ -1382,7 +1381,7 @@ int domain_context_mapping_one(
if ( iommu_hwdom_passthrough && is_hardware_domain(domain) )
{
- context_set_translation_type(*context, CONTEXT_TT_PASS_THRU);
+ context->tt = CONTEXT_TT_PASS_THRU;
}
else
{
@@ -1397,11 +1396,11 @@ int domain_context_mapping_one(
return -ENOMEM;
}
- context_set_address_root(*context, pgd_maddr);
+ context->slptptr = paddr_to_pfn(pgd_maddr);
if ( ats_enabled && ecap_dev_iotlb(iommu->ecap) )
- context_set_translation_type(*context, CONTEXT_TT_DEV_IOTLB);
+ context->tt = CONTEXT_TT_DEV_IOTLB;
else
- context_set_translation_type(*context, CONTEXT_TT_MULTI_LEVEL);
+ context->tt = CONTEXT_TT_MULTI_LEVEL;
spin_unlock(&hd->arch.mapping_lock);
}
@@ -1413,9 +1412,10 @@ int domain_context_mapping_one(
return -EFAULT;
}
- context_set_address_width(*context, level_to_agaw(iommu->nr_pt_levels));
- context_set_fault_enable(*context);
- context_set_present(*context);
+ context->aw = level_to_agaw(iommu->nr_pt_levels);
+ context->fpd = false;
+ smp_wmb();
+ context->p = true;
iommu_sync_cache(context, sizeof(struct context_entry));
spin_unlock(&iommu->lock);
@@ -1567,17 +1567,19 @@ int domain_context_unmap_one(
context_entries = (struct context_entry *)map_vtd_domain_page(maddr);
context = &context_entries[devfn];
- if ( !context_present(*context) )
+ if ( !context->p )
{
spin_unlock(&iommu->lock);
unmap_vtd_domain_page(context_entries);
return 0;
}
- context_clear_present(*context);
- context_clear_entry(*context);
+ context->p = false;
+ smp_wmb();
iommu_sync_cache(context, sizeof(struct context_entry));
+ context->val = 0; /* No need to sync; present bit is already cleared */
+
iommu_domid= domain_iommu_domid(domain, iommu);
if ( iommu_domid == -1 )
{
diff --git a/xen/drivers/passthrough/vtd/iommu.h
b/xen/drivers/passthrough/vtd/iommu.h
index b14628eec260..33b1abf98526 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -198,37 +198,34 @@ struct root_entry {
};
};
};
+#define ROOT_ENTRY_NR (PAGE_SIZE_4K / sizeof(struct root_entry))
struct context_entry {
- u64 lo;
- u64 hi;
-};
-#define ROOT_ENTRY_NR (PAGE_SIZE_4K/sizeof(struct root_entry))
-#define context_present(c) ((c).lo & 1)
-#define context_fault_disable(c) (((c).lo >> 1) & 1)
-#define context_translation_type(c) (((c).lo >> 2) & 3)
-#define context_address_root(c) ((c).lo & PAGE_MASK_4K)
-#define context_address_width(c) ((c).hi & 7)
-#define context_domain_id(c) (((c).hi >> 8) & ((1 << 16) - 1))
+ union {
+ __uint128_t val;
+ struct { uint64_t lo, hi; };
+ struct {
+ /* 0 - 63 */
+ bool p:1;
+ bool fpd:1;
+ uint64_t tt:2;
-#define context_set_present(c) do {(c).lo |= 1;} while(0)
-#define context_clear_present(c) do {(c).lo &= ~1;} while(0)
-#define context_set_fault_enable(c) \
- do {(c).lo &= (((u64)-1) << 2) | 1;} while(0)
-
-#define context_set_translation_type(c, val) do { \
- (c).lo &= (((u64)-1) << 4) | 3; \
- (c).lo |= (val & 3) << 2; \
- } while(0)
#define CONTEXT_TT_MULTI_LEVEL 0
#define CONTEXT_TT_DEV_IOTLB 1
#define CONTEXT_TT_PASS_THRU 2
-#define context_set_address_root(c, val) \
- do {(c).lo &= 0xfff; (c).lo |= (val) & PAGE_MASK_4K ;} while(0)
-#define context_set_address_width(c, val) \
- do {(c).hi &= 0xfffffff8; (c).hi |= (val) & 7;} while(0)
-#define context_clear_entry(c) do {(c).lo = 0; (c).hi = 0;} while(0)
+ unsigned int reserved0:8;
+ uint64_t slptptr:52;
+
+ /* 64 - 127 */
+ unsigned int aw:3;
+ unsigned int ignored:4;
+ unsigned int reserved1:1;
+ unsigned int did:16;
+ uint64_t reserved2:40;
+ };
+ };
+};
/* page table handling */
#define LEVEL_STRIDE (9)
diff --git a/xen/drivers/passthrough/vtd/utils.c
b/xen/drivers/passthrough/vtd/utils.c
index 5f25a86a535c..4bca160bc663 100644
--- a/xen/drivers/passthrough/vtd/utils.c
+++ b/xen/drivers/passthrough/vtd/utils.c
@@ -129,17 +129,17 @@ void print_vtd_entries(struct vtd_iommu *iommu, int bus,
int devfn, u64 gmfn)
return;
}
- val = ctxt_entry[devfn].lo;
- printk(" context[%02x] = %"PRIx64"_%"PRIx64"\n",
- devfn, ctxt_entry[devfn].hi, val);
- if ( !context_present(ctxt_entry[devfn]) )
+ printk(" context[%02x] = %"PRIx64"_%"PRIx64"\n", devfn,
+ ctxt_entry[devfn].hi, ctxt_entry[devfn].lo);
+ if ( !ctxt_entry[devfn].p )
{
unmap_vtd_domain_page(ctxt_entry);
printk(" ctxt_entry[%02x] not present\n", devfn);
return;
}
- level = agaw_to_level(context_address_width(ctxt_entry[devfn]));
+ level = agaw_to_level(ctxt_entry[devfn].aw);
+ val = pfn_to_paddr(ctxt_entry[devfn].slptptr);
unmap_vtd_domain_page(ctxt_entry);
if ( level != VTD_PAGE_TABLE_LEVEL_3 &&
level != VTD_PAGE_TABLE_LEVEL_4)
diff --git a/xen/drivers/passthrough/vtd/x86/ats.c
b/xen/drivers/passthrough/vtd/x86/ats.c
index fec969ef75bb..cb057ced3cf7 100644
--- a/xen/drivers/passthrough/vtd/x86/ats.c
+++ b/xen/drivers/passthrough/vtd/x86/ats.c
@@ -76,7 +76,6 @@ static bool device_in_domain(const struct vtd_iommu *iommu,
{
struct root_entry *root_entry, *root_entries;
struct context_entry *context_entry, *context_entries = NULL;
- unsigned int tt;
bool found = false;
if ( unlikely(!iommu->root_maddr) )
@@ -92,11 +91,10 @@ static bool device_in_domain(const struct vtd_iommu *iommu,
context_entries = map_vtd_domain_page(root_entry->ctp);
context_entry = &context_entries[pdev->devfn];
- if ( context_domain_id(*context_entry) != did )
+ if ( context_entry->did != did )
goto out;
- tt = context_translation_type(*context_entry);
- if ( tt != CONTEXT_TT_DEV_IOTLB )
+ if ( context_entry->tt != CONTEXT_TT_DEV_IOTLB )
goto out;
found = true;
--
2.20.1
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