From: Paul Durrant <pdurrant@amazon.com>
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@amazon.com>
---
Cc: Kevin Tian <kevin.tian@intel.com>
v4:
- New in v4
---
xen/drivers/passthrough/vtd/iommu.c | 8 ++--
xen/drivers/passthrough/vtd/iommu.h | 65 +++++++++++++++++----------
xen/drivers/passthrough/vtd/utils.c | 6 +--
xen/drivers/passthrough/vtd/x86/ats.c | 2 +-
4 files changed, 49 insertions(+), 32 deletions(-)
diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 76025f6ccd..766d33058e 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)
@@ -121,7 +119,7 @@ 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_set_did(*context, i);
return 0;
}
@@ -135,7 +133,7 @@ static int context_get_domain_id(struct context_entry *context,
{
nr_dom = cap_ndoms(iommu->cap);
- dom_index = context_domain_id(*context);
+ dom_index = context_did(*context);
if ( dom_index < nr_dom && iommu->domid_map )
domid = iommu->domid_map[dom_index];
@@ -1396,7 +1394,7 @@ int domain_context_mapping_one(
return -ENOMEM;
}
- context_set_address_root(*context, pgd_maddr);
+ context_set_slptp(*context, pgd_maddr);
if ( ats_enabled && ecap_dev_iotlb(iommu->ecap) )
context_set_translation_type(*context, CONTEXT_TT_DEV_IOTLB);
else
diff --git a/xen/drivers/passthrough/vtd/iommu.h b/xen/drivers/passthrough/vtd/iommu.h
index 031ac5f66c..509d13918a 100644
--- a/xen/drivers/passthrough/vtd/iommu.h
+++ b/xen/drivers/passthrough/vtd/iommu.h
@@ -199,6 +199,7 @@ struct root_entry {
};
};
};
+#define ROOT_ENTRY_NR (PAGE_SIZE_4K / sizeof(struct root_entry))
#define root_present(r) (r).p
#define set_root_present(r) do { (r).p = 1; } while (0)
@@ -208,35 +209,53 @@ struct root_entry {
do { (r).ctp = ((val) >> PAGE_SHIFT_4K); } while (0)
struct context_entry {
- u64 lo;
- u64 hi;
+ union {
+ __uint128_t val;
+ struct { uint64_t lo, hi; };
+ struct {
+ /* 0 - 63 */
+ uint64_t p:1;
+ uint64_t fpd:1;
+ uint64_t tt:2;
+ uint64_t reserved0:8;
+ uint64_t slptp:52;
+
+ /* 64 - 127 */
+ uint64_t aw:3;
+ uint64_t ignored:4;
+ uint64_t reserved1:1;
+ uint64_t did:16;
+ uint64_t reserved2:40;
+ };
+ };
};
-#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))
-
-#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_present(c) (c).p
+#define context_set_present(c) do { (c).p = 1; } while (0)
+#define context_clear_present(c) do { (c).p = 0; } while (0)
+
+#define context_fault_disable(c) (c).fpd
+#define context_set_fault_enable(c) do { (c).fpd = 1; } while (0)
+
+#define context_translation_type(c) (c).tt
+#define context_set_translation_type(c, val) do { (c).tt = val; } 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_slptp(c) ((c).slptp << PAGE_SHIFT_4K)
+#define context_set_slptp(c, val) \
+ do { (c).slptp = (val) >> PAGE_SHIFT_4K; } while (0)
+
+#define context_address_width(c) (c).aw
#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)
+ do { (c).aw = (val); } while (0)
+
+#define context_did(c) (c).did
+#define context_set_did(c, val) \
+ do { (c).did = (val); } while (0)
+
+#define context_clear_entry(c) do { (c).val = 0; } while (0)
/* page table handling */
#define LEVEL_STRIDE (9)
diff --git a/xen/drivers/passthrough/vtd/utils.c b/xen/drivers/passthrough/vtd/utils.c
index 4c85242894..eae0c43269 100644
--- a/xen/drivers/passthrough/vtd/utils.c
+++ b/xen/drivers/passthrough/vtd/utils.c
@@ -129,9 +129,8 @@ 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);
+ printk(" context[%02x] = %"PRIx64"_%"PRIx64"\n", devfn,
+ ctxt_entry[devfn].hi, ctxt_entry[devfn].lo);
if ( !context_present(ctxt_entry[devfn]) )
{
unmap_vtd_domain_page(ctxt_entry);
@@ -140,6 +139,7 @@ void print_vtd_entries(struct vtd_iommu *iommu, int bus, int devfn, u64 gmfn)
}
level = agaw_to_level(context_address_width(ctxt_entry[devfn]));
+ val = context_slptp(ctxt_entry[devfn]);
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 8369415dcc..a7bbd3198a 100644
--- a/xen/drivers/passthrough/vtd/x86/ats.c
+++ b/xen/drivers/passthrough/vtd/x86/ats.c
@@ -92,7 +92,7 @@ static bool device_in_domain(const struct vtd_iommu *iommu,
context_entries = map_vtd_domain_page(root_ctp(*root_entry));
context_entry = &context_entries[pdev->devfn];
- if ( context_domain_id(*context_entry) != did )
+ if ( context_did(*context_entry) != did )
goto out;
tt = context_translation_type(*context_entry);
--
2.20.1
> From: Paul Durrant <paul@xen.org>
> Sent: Tuesday, August 4, 2020 9:42 PM
>
> From: Paul Durrant <pdurrant@amazon.com>
>
> This removes the need for much shifting, masking and several magic
> numbers.
> On the whole it makes the code quite a bit more readable.
similarly, I feel the readability is worse such as slptp. We may use bitfeld
to define the structure, but the function name may be kept with current
way...
Thanks
kevin
>
> Signed-off-by: Paul Durrant <pdurrant@amazon.com>
> ---
> Cc: Kevin Tian <kevin.tian@intel.com>
>
> v4:
> - New in v4
> ---
> xen/drivers/passthrough/vtd/iommu.c | 8 ++--
> xen/drivers/passthrough/vtd/iommu.h | 65 +++++++++++++++++----------
> xen/drivers/passthrough/vtd/utils.c | 6 +--
> xen/drivers/passthrough/vtd/x86/ats.c | 2 +-
> 4 files changed, 49 insertions(+), 32 deletions(-)
>
> diff --git a/xen/drivers/passthrough/vtd/iommu.c
> b/xen/drivers/passthrough/vtd/iommu.c
> index 76025f6ccd..766d33058e 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)
> @@ -121,7 +119,7 @@ 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_set_did(*context, i);
> return 0;
> }
>
> @@ -135,7 +133,7 @@ static int context_get_domain_id(struct
> context_entry *context,
> {
> nr_dom = cap_ndoms(iommu->cap);
>
> - dom_index = context_domain_id(*context);
> + dom_index = context_did(*context);
>
> if ( dom_index < nr_dom && iommu->domid_map )
> domid = iommu->domid_map[dom_index];
> @@ -1396,7 +1394,7 @@ int domain_context_mapping_one(
> return -ENOMEM;
> }
>
> - context_set_address_root(*context, pgd_maddr);
> + context_set_slptp(*context, pgd_maddr);
> if ( ats_enabled && ecap_dev_iotlb(iommu->ecap) )
> context_set_translation_type(*context, CONTEXT_TT_DEV_IOTLB);
> else
> diff --git a/xen/drivers/passthrough/vtd/iommu.h
> b/xen/drivers/passthrough/vtd/iommu.h
> index 031ac5f66c..509d13918a 100644
> --- a/xen/drivers/passthrough/vtd/iommu.h
> +++ b/xen/drivers/passthrough/vtd/iommu.h
> @@ -199,6 +199,7 @@ struct root_entry {
> };
> };
> };
> +#define ROOT_ENTRY_NR (PAGE_SIZE_4K / sizeof(struct root_entry))
>
> #define root_present(r) (r).p
> #define set_root_present(r) do { (r).p = 1; } while (0)
> @@ -208,35 +209,53 @@ struct root_entry {
> do { (r).ctp = ((val) >> PAGE_SHIFT_4K); } while (0)
>
> struct context_entry {
> - u64 lo;
> - u64 hi;
> + union {
> + __uint128_t val;
> + struct { uint64_t lo, hi; };
> + struct {
> + /* 0 - 63 */
> + uint64_t p:1;
> + uint64_t fpd:1;
> + uint64_t tt:2;
> + uint64_t reserved0:8;
> + uint64_t slptp:52;
> +
> + /* 64 - 127 */
> + uint64_t aw:3;
> + uint64_t ignored:4;
> + uint64_t reserved1:1;
> + uint64_t did:16;
> + uint64_t reserved2:40;
> + };
> + };
> };
> -#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))
> -
> -#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_present(c) (c).p
> +#define context_set_present(c) do { (c).p = 1; } while (0)
> +#define context_clear_present(c) do { (c).p = 0; } while (0)
> +
> +#define context_fault_disable(c) (c).fpd
> +#define context_set_fault_enable(c) do { (c).fpd = 1; } while (0)
> +
> +#define context_translation_type(c) (c).tt
> +#define context_set_translation_type(c, val) do { (c).tt = val; } 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_slptp(c) ((c).slptp << PAGE_SHIFT_4K)
> +#define context_set_slptp(c, val) \
> + do { (c).slptp = (val) >> PAGE_SHIFT_4K; } while (0)
> +
> +#define context_address_width(c) (c).aw
> #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)
> + do { (c).aw = (val); } while (0)
> +
> +#define context_did(c) (c).did
> +#define context_set_did(c, val) \
> + do { (c).did = (val); } while (0)
> +
> +#define context_clear_entry(c) do { (c).val = 0; } while (0)
>
> /* page table handling */
> #define LEVEL_STRIDE (9)
> diff --git a/xen/drivers/passthrough/vtd/utils.c
> b/xen/drivers/passthrough/vtd/utils.c
> index 4c85242894..eae0c43269 100644
> --- a/xen/drivers/passthrough/vtd/utils.c
> +++ b/xen/drivers/passthrough/vtd/utils.c
> @@ -129,9 +129,8 @@ 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);
> + printk(" context[%02x] = %"PRIx64"_%"PRIx64"\n", devfn,
> + ctxt_entry[devfn].hi, ctxt_entry[devfn].lo);
> if ( !context_present(ctxt_entry[devfn]) )
> {
> unmap_vtd_domain_page(ctxt_entry);
> @@ -140,6 +139,7 @@ void print_vtd_entries(struct vtd_iommu *iommu, int
> bus, int devfn, u64 gmfn)
> }
>
> level = agaw_to_level(context_address_width(ctxt_entry[devfn]));
> + val = context_slptp(ctxt_entry[devfn]);
> 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 8369415dcc..a7bbd3198a 100644
> --- a/xen/drivers/passthrough/vtd/x86/ats.c
> +++ b/xen/drivers/passthrough/vtd/x86/ats.c
> @@ -92,7 +92,7 @@ static bool device_in_domain(const struct vtd_iommu
> *iommu,
>
> context_entries = map_vtd_domain_page(root_ctp(*root_entry));
> context_entry = &context_entries[pdev->devfn];
> - if ( context_domain_id(*context_entry) != did )
> + if ( context_did(*context_entry) != did )
> goto out;
>
> tt = context_translation_type(*context_entry);
> --
> 2.20.1
On 04.08.2020 15:42, Paul Durrant wrote:
> @@ -208,35 +209,53 @@ struct root_entry {
> do { (r).ctp = ((val) >> PAGE_SHIFT_4K); } while (0)
>
> struct context_entry {
> - u64 lo;
> - u64 hi;
> + union {
> + __uint128_t val;
> + struct { uint64_t lo, hi; };
> + struct {
> + /* 0 - 63 */
> + uint64_t p:1;
> + uint64_t fpd:1;
> + uint64_t tt:2;
> + uint64_t reserved0:8;
> + uint64_t slptp:52;
> +
> + /* 64 - 127 */
> + uint64_t aw:3;
> + uint64_t ignored:4;
> + uint64_t reserved1:1;
> + uint64_t did:16;
> + uint64_t reserved2:40;
> + };
> + };
> };
> -#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))
> -
> -#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_present(c) (c).p
> +#define context_set_present(c) do { (c).p = 1; } while (0)
> +#define context_clear_present(c) do { (c).p = 0; } while (0)
> +
> +#define context_fault_disable(c) (c).fpd
> +#define context_set_fault_enable(c) do { (c).fpd = 1; } while (0)
> +
> +#define context_translation_type(c) (c).tt
> +#define context_set_translation_type(c, val) do { (c).tt = val; } 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_slptp(c) ((c).slptp << PAGE_SHIFT_4K)
> +#define context_set_slptp(c, val) \
> + do { (c).slptp = (val) >> PAGE_SHIFT_4K; } while (0)
Presumably "slptp" is in line with the doc, but "address_root" is
quite a bit more readable. I wonder if I could talk you into
restoring the old (or some similar) names.
More generally, and more so here than perhaps already on the previous
patch - are these helper macros useful to have anymore?
> +#define context_address_width(c) (c).aw
> #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)
> + do { (c).aw = (val); } while (0)
> +
> +#define context_did(c) (c).did
> +#define context_set_did(c, val) \
> + do { (c).did = (val); } while (0)
> +
> +#define context_clear_entry(c) do { (c).val = 0; } while (0)
While this is in line with previous code, I'm concerned:
domain_context_unmap_one() has
context_clear_present(*context);
context_clear_entry(*context);
No barrier means no guarantee of ordering. I'd drop clear_present()
here and make clear_entry() properly ordered. This, I think, will at
the same time render the __uint128_t field unused and hence
unnecessary again.
Also comments given on the previous patch apply respectively here.
Jan
> -----Original Message-----
> From: Jan Beulich <jbeulich@suse.com>
> Sent: 06 August 2020 13:47
> To: Paul Durrant <paul@xen.org>
> Cc: xen-devel@lists.xenproject.org; Paul Durrant <pdurrant@amazon.com>; Kevin Tian
> <kevin.tian@intel.com>
> Subject: Re: [PATCH v4 13/14] vtd: use a bit field for context_entry
>
> On 04.08.2020 15:42, Paul Durrant wrote:
> > @@ -208,35 +209,53 @@ struct root_entry {
> > do { (r).ctp = ((val) >> PAGE_SHIFT_4K); } while (0)
> >
> > struct context_entry {
> > - u64 lo;
> > - u64 hi;
> > + union {
> > + __uint128_t val;
> > + struct { uint64_t lo, hi; };
> > + struct {
> > + /* 0 - 63 */
> > + uint64_t p:1;
> > + uint64_t fpd:1;
> > + uint64_t tt:2;
> > + uint64_t reserved0:8;
> > + uint64_t slptp:52;
> > +
> > + /* 64 - 127 */
> > + uint64_t aw:3;
> > + uint64_t ignored:4;
> > + uint64_t reserved1:1;
> > + uint64_t did:16;
> > + uint64_t reserved2:40;
> > + };
> > + };
> > };
> > -#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))
> > -
> > -#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_present(c) (c).p
> > +#define context_set_present(c) do { (c).p = 1; } while (0)
> > +#define context_clear_present(c) do { (c).p = 0; } while (0)
> > +
> > +#define context_fault_disable(c) (c).fpd
> > +#define context_set_fault_enable(c) do { (c).fpd = 1; } while (0)
> > +
> > +#define context_translation_type(c) (c).tt
> > +#define context_set_translation_type(c, val) do { (c).tt = val; } 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_slptp(c) ((c).slptp << PAGE_SHIFT_4K)
> > +#define context_set_slptp(c, val) \
> > + do { (c).slptp = (val) >> PAGE_SHIFT_4K; } while (0)
>
> Presumably "slptp" is in line with the doc, but "address_root" is
> quite a bit more readable. I wonder if I could talk you into
> restoring the old (or some similar) names.
The problem with 'root' in the VT-d code is that it is ambiguous between this case and manipulations of 'root entries', which is why I moved away from it. The spec refers to 'slptptr' but I shortened it to 'slptp' for consistency with the root 'ctp'... I should really use the name from the spec. though.
I will add a comment above the macro stating what the 'slptptr' is too.
>
> More generally, and more so here than perhaps already on the previous
> patch - are these helper macros useful to have anymore?
>
Less useful. I was worried about ditching them causing the patches to balloon in size but maybe they won't... I'll see.
> > +#define context_address_width(c) (c).aw
> > #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)
> > + do { (c).aw = (val); } while (0)
> > +
> > +#define context_did(c) (c).did
> > +#define context_set_did(c, val) \
> > + do { (c).did = (val); } while (0)
> > +
> > +#define context_clear_entry(c) do { (c).val = 0; } while (0)
>
> While this is in line with previous code, I'm concerned:
> domain_context_unmap_one() has
>
> context_clear_present(*context);
> context_clear_entry(*context);
>
> No barrier means no guarantee of ordering. I'd drop clear_present()
> here and make clear_entry() properly ordered. This, I think, will at
> the same time render the __uint128_t field unused and hence
> unnecessary again.
I'd prefer to keep both with a barrier, particularly if I get rid of the macros.
Paul
>
> Also comments given on the previous patch apply respectively here.
>
> Jan
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