[PATCH] x86/hvm: Drop pat_entry_2_pte_flags

Andrew Cooper posted 1 patch 1 year, 2 months ago
Test gitlab-ci failed
Patches applied successfully (tree, apply log)
git fetch https://gitlab.com/xen-project/patchew/xen tags/patchew/20230116120201.2829-1-andrew.cooper3@citrix.com
xen/arch/x86/hvm/mtrr.c | 9 +--------
1 file changed, 1 insertion(+), 8 deletions(-)
[PATCH] x86/hvm: Drop pat_entry_2_pte_flags
Posted by Andrew Cooper 1 year, 2 months ago
Converting from PAT to PTE is trivial, and shorter to encode with bitwise
logic than the space taken by a table counting from 0 to 7 in non-adjacent
bits.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Roger Pau Monné <roger.pau@citrix.com>
CC: Wei Liu <wl@xen.org>

Noticed while reviewing other shadow patches
---
 xen/arch/x86/hvm/mtrr.c | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/mtrr.c b/xen/arch/x86/hvm/mtrr.c
index 093103f6c768..344edc2d6a96 100644
--- a/xen/arch/x86/hvm/mtrr.c
+++ b/xen/arch/x86/hvm/mtrr.c
@@ -29,13 +29,6 @@
 /* Get page attribute fields (PAn) from PAT MSR. */
 #define pat_cr_2_paf(pat_cr,n)  ((((uint64_t)pat_cr) >> ((n)<<3)) & 0xff)
 
-/* PAT entry to PTE flags (PAT, PCD, PWT bits). */
-static const uint8_t pat_entry_2_pte_flags[8] = {
-    0,           _PAGE_PWT,
-    _PAGE_PCD,   _PAGE_PCD | _PAGE_PWT,
-    _PAGE_PAT,   _PAGE_PAT | _PAGE_PWT,
-    _PAGE_PAT | _PAGE_PCD, _PAGE_PAT | _PAGE_PCD | _PAGE_PWT };
-
 /* Effective mm type lookup table, according to MTRR and PAT. */
 static const uint8_t mm_type_tbl[MTRR_NUM_TYPES][X86_NUM_MT] = {
 #define RS MEMORY_NUM_TYPES
@@ -117,7 +110,7 @@ uint8_t pat_type_2_pte_flags(uint8_t pat_type)
     if ( unlikely(pat_entry == INVALID_MEM_TYPE) )
         pat_entry = pat_entry_tbl[X86_MT_UC];
 
-    return pat_entry_2_pte_flags[pat_entry];
+    return cacheattr_to_pte_flags(pat_entry);
 }
 
 int hvm_vcpu_cacheattr_init(struct vcpu *v)
-- 
2.11.0


Re: [PATCH] x86/hvm: Drop pat_entry_2_pte_flags
Posted by Jan Beulich 1 year, 2 months ago
On 16.01.2023 13:02, Andrew Cooper wrote:
> Converting from PAT to PTE is trivial, and shorter to encode with bitwise
> logic than the space taken by a table counting from 0 to 7 in non-adjacent
> bits.
> 
> No functional change.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>

Acked-by: Jan Beulich <jbeulich@suse.com>