[PATCH v2 1/2] x86/vmx: Introduce a bitfield structure for EPT_VIOLATION EXIT_QUALIFICATIONs

[Andrew Cooper <andrew.cooper3@citrix.com>]

This results in rather more readable code.  No functional change.

All fields currently specified are included, but commented out as no support
for their use is present.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: Jan Beulich <JBeulich@suse.com>
CC: Jun Nakajima <jun.nakajima@intel.com>
CC: Kevin Tian <kevin.tian@intel.com>

v2:
 * Use a transparent union rather than modifying the caller of
   ept_handle_violation()
 * Drop the extranious commented out bitfield names, but keep eff_user_exec so
   gla_{valid,fault} are appropriately located.
---
 xen/arch/x86/hvm/vmx/vmx.c        | 35 ++++++++++++++++-------------------
 xen/include/asm-x86/hvm/vmx/vmx.h | 25 +++++++++----------------
 xen/include/xen/compiler.h        |  1 +
 3 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 5aada98..d3d98da 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -2986,7 +2986,7 @@ static void vmx_wbinvd_intercept(void)
         wbinvd();
 }
 
-static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
+static void ept_handle_violation(ept_qual_t q, paddr_t gpa)
 {
     unsigned long gla, gfn = gpa >> PAGE_SHIFT;
     mfn_t mfn;
@@ -3006,13 +3006,10 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
      *   Volume 3C: System Programming Guide, Part 3
      */
     struct npfec npfec = {
-        .read_access = !!(qualification & EPT_READ_VIOLATION) ||
-                       !!(qualification & EPT_WRITE_VIOLATION),
-        .write_access = !!(qualification & EPT_WRITE_VIOLATION),
-        .insn_fetch = !!(qualification & EPT_EXEC_VIOLATION),
-        .present = !!(qualification & (EPT_EFFECTIVE_READ |
-                                       EPT_EFFECTIVE_WRITE |
-                                       EPT_EFFECTIVE_EXEC))
+        .read_access = q.read || q.write,
+        .write_access = q.write,
+        .insn_fetch = q.fetch,
+        .present = q.eff_read || q.eff_write || q.eff_exec,
     };
 
     if ( tb_init_done )
@@ -3025,17 +3022,17 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
         } _d;
 
         _d.gpa = gpa;
-        _d.qualification = qualification;
+        _d.qualification = q.raw;
         _d.mfn = mfn_x(get_gfn_query_unlocked(d, gfn, &_d.p2mt));
 
         __trace_var(TRC_HVM_NPF, 0, sizeof(_d), &_d);
     }
 
-    if ( qualification & EPT_GLA_VALID )
+    if ( q.gla_valid )
     {
         __vmread(GUEST_LINEAR_ADDRESS, &gla);
         npfec.gla_valid = 1;
-        if( qualification & EPT_GLA_FAULT )
+        if( q.gla_fault )
             npfec.kind = npfec_kind_with_gla;
         else
             npfec.kind = npfec_kind_in_gpt;
@@ -3065,18 +3062,18 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
     mfn = get_gfn_query_unlocked(d, gfn, &p2mt);
     gprintk(XENLOG_ERR,
             "EPT violation %#lx (%c%c%c/%c%c%c) gpa %#"PRIpaddr" mfn %#lx type %i\n",
-            qualification,
-            (qualification & EPT_READ_VIOLATION) ? 'r' : '-',
-            (qualification & EPT_WRITE_VIOLATION) ? 'w' : '-',
-            (qualification & EPT_EXEC_VIOLATION) ? 'x' : '-',
-            (qualification & EPT_EFFECTIVE_READ) ? 'r' : '-',
-            (qualification & EPT_EFFECTIVE_WRITE) ? 'w' : '-',
-            (qualification & EPT_EFFECTIVE_EXEC) ? 'x' : '-',
+            q.raw,
+            q.read  ? 'r' : '-',
+            q.write ? 'w' : '-',
+            q.fetch ? 'x' : '-',
+            q.eff_read  ? 'r' : '-',
+            q.eff_write ? 'w' : '-',
+            q.eff_exec  ? 'x' : '-',
             gpa, mfn_x(mfn), p2mt);
 
     ept_walk_table(d, gfn);
 
-    if ( qualification & EPT_GLA_VALID )
+    if ( q.gla_valid )
         gprintk(XENLOG_ERR, " --- GLA %#lx\n", gla);
 
     domain_crash(d);
diff --git a/xen/include/asm-x86/hvm/vmx/vmx.h b/xen/include/asm-x86/hvm/vmx/vmx.h
index 4bf4d50..1c5ae11 100644
--- a/xen/include/asm-x86/hvm/vmx/vmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vmx.h
@@ -578,22 +578,15 @@ void vmx_pi_hooks_assign(struct domain *d);
 void vmx_pi_hooks_deassign(struct domain *d);
 
 /* EPT violation qualifications definitions */
-#define _EPT_READ_VIOLATION         0
-#define EPT_READ_VIOLATION          (1UL<<_EPT_READ_VIOLATION)
-#define _EPT_WRITE_VIOLATION        1
-#define EPT_WRITE_VIOLATION         (1UL<<_EPT_WRITE_VIOLATION)
-#define _EPT_EXEC_VIOLATION         2
-#define EPT_EXEC_VIOLATION          (1UL<<_EPT_EXEC_VIOLATION)
-#define _EPT_EFFECTIVE_READ         3
-#define EPT_EFFECTIVE_READ          (1UL<<_EPT_EFFECTIVE_READ)
-#define _EPT_EFFECTIVE_WRITE        4
-#define EPT_EFFECTIVE_WRITE         (1UL<<_EPT_EFFECTIVE_WRITE)
-#define _EPT_EFFECTIVE_EXEC         5
-#define EPT_EFFECTIVE_EXEC          (1UL<<_EPT_EFFECTIVE_EXEC)
-#define _EPT_GLA_VALID              7
-#define EPT_GLA_VALID               (1UL<<_EPT_GLA_VALID)
-#define _EPT_GLA_FAULT              8
-#define EPT_GLA_FAULT               (1UL<<_EPT_GLA_FAULT)
+typedef union __transparent__ ept_qual {
+    unsigned long raw;
+    struct {
+        bool read:1, write:1, fetch:1,
+            eff_read:1, eff_write:1, eff_exec:1, /* eff_user_exec */:1,
+            gla_valid:1,
+            gla_fault:1; /* Valid iff gla_valid. */
+    };
+} ept_qual_t;
 
 #define EPT_L4_PAGETABLE_SHIFT      39
 #define EPT_PAGETABLE_ENTRIES       512
diff --git a/xen/include/xen/compiler.h b/xen/include/xen/compiler.h
index 33f0b96..e800709 100644
--- a/xen/include/xen/compiler.h
+++ b/xen/include/xen/compiler.h
@@ -47,6 +47,7 @@
 
 #define __attribute_pure__  __attribute__((__pure__))
 #define __attribute_const__ __attribute__((__const__))
+#define __transparent__     __attribute__((__transparent_union__))
 
 /*
  * The difference between the following two attributes is that __used is
-- 
2.1.4


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