x86: consolidate boolean inputs in hvm and p2m into a shared bitmap

This patch consolidates the boolean input parameters of
hvm_hap_nested_page_fault and p2m_mem_access_check into a common bitmap
and defines the bitmap members accordingly.

Signed-off-by: Tamas K Lengyel <tamas.lengyel@zentific.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Tim Deegan <tim@xen.org>

xen/arch/x86/hvm/hvm.c

@@ -2723,12 +2723,8 @@ void hvm_inject_page_fault(int errcode, unsigned long cr2)
     hvm_inject_trap(&trap);
 }
 
-int hvm_hap_nested_page_fault(paddr_t gpa,
-                              bool_t gla_valid,
-                              unsigned long gla,
-                              bool_t access_r,
-                              bool_t access_w,
-                              bool_t access_x)
+int hvm_hap_nested_page_fault(paddr_t gpa, unsigned long gla,
+                              struct npfec npfec)
 {
     unsigned long gfn = gpa >> PAGE_SHIFT;
     p2m_type_t p2mt;
@@ -2757,8 +2753,11 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
          * into l1 guest if not fixable. The algorithm is
          * the same as for shadow paging.
          */
-        rv = nestedhvm_hap_nested_page_fault(v, &gpa,
-                                             access_r, access_w, access_x);
+
+         rv = nestedhvm_hap_nested_page_fault(v, &gpa,
+                                              npfec.read_access,
+                                              npfec.write_access,
+                                              npfec.insn_fetch);
         switch (rv) {
         case NESTEDHVM_PAGEFAULT_DONE:
         case NESTEDHVM_PAGEFAULT_RETRY:
@@ -2797,47 +2796,49 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
 
     p2m = p2m_get_hostp2m(v->domain);
     mfn = get_gfn_type_access(p2m, gfn, &p2mt, &p2ma, 
-                              P2M_ALLOC | (access_w ? P2M_UNSHARE : 0), NULL);
+                              P2M_ALLOC | npfec.write_access ? P2M_UNSHARE : 0,
+                              NULL);
 
     /* Check access permissions first, then handle faults */
     if ( mfn_x(mfn) != INVALID_MFN )
     {
-        int violation = 0;
+        bool_t violation;
+
         /* If the access is against the permissions, then send to mem_event */
-        switch (p2ma) 
+        switch (p2ma)
         {
         case p2m_access_n:
         case p2m_access_n2rwx:
         default:
-            violation = access_r || access_w || access_x;
+            violation = npfec.read_access || npfec.write_access || npfec.insn_fetch;
             break;
         case p2m_access_r:
-            violation = access_w || access_x;
+            violation = npfec.write_access || npfec.insn_fetch;
             break;
         case p2m_access_w:
-            violation = access_r || access_x;
+            violation = npfec.read_access || npfec.insn_fetch;
             break;
         case p2m_access_x:
-            violation = access_r || access_w;
+            violation = npfec.read_access || npfec.write_access;
             break;
         case p2m_access_rx:
         case p2m_access_rx2rw:
-            violation = access_w;
+            violation = npfec.write_access;
             break;
         case p2m_access_wx:
-            violation = access_r;
+            violation = npfec.read_access;
             break;
         case p2m_access_rw:
-            violation = access_x;
+            violation = npfec.insn_fetch;
             break;
         case p2m_access_rwx:
+            violation = 0;
             break;
         }
 
         if ( violation )
         {
-            if ( p2m_mem_access_check(gpa, gla_valid, gla, access_r, 
-                                        access_w, access_x, &req_ptr) )
+            if ( p2m_mem_access_check(gpa, gla, npfec, &req_ptr) )
             {
                 fall_through = 1;
             } else {
@@ -2853,7 +2854,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
      * to the mmio handler.
      */
     if ( (p2mt == p2m_mmio_dm) || 
-         (access_w && (p2mt == p2m_ram_ro)) )
+         (npfec.write_access && (p2mt == p2m_ram_ro)) )
     {
         put_gfn(p2m->domain, gfn);
 
@@ -2872,7 +2873,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
         paged = 1;
 
     /* Mem sharing: unshare the page and try again */
-    if ( access_w && (p2mt == p2m_ram_shared) )
+    if ( npfec.write_access && (p2mt == p2m_ram_shared) )
     {
         ASSERT(!p2m_is_nestedp2m(p2m));
         sharing_enomem = 
@@ -2889,7 +2890,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
          * a large page, we do not change other pages type within that large
          * page.
          */
-        if ( access_w )
+        if ( npfec.write_access )
         {
             paging_mark_dirty(v->domain, mfn_x(mfn));
             p2m_change_type_one(v->domain, gfn, p2m_ram_logdirty, p2m_ram_rw);
@@ -2899,7 +2900,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa,
     }
 
     /* Shouldn't happen: Maybe the guest was writing to a r/o grant mapping? */
-    if ( access_w && (p2mt == p2m_grant_map_ro) )
+    if ( npfec.write_access && (p2mt == p2m_grant_map_ro) )
     {
         gdprintk(XENLOG_WARNING,
                  "trying to write to read-only grant mapping\n");

xen/arch/x86/hvm/svm/svm.c

@@ -1394,7 +1394,7 @@ const struct hvm_function_table * __init start_svm(void)
 }
 
 static void svm_do_nested_pgfault(struct vcpu *v,
-    struct cpu_user_regs *regs, uint32_t npfec, paddr_t gpa)
+    struct cpu_user_regs *regs, uint32_t pfec, paddr_t gpa)
 {
     int ret;
     unsigned long gfn = gpa >> PAGE_SHIFT;
@@ -1403,10 +1403,13 @@ static void svm_do_nested_pgfault(struct vcpu *v,
     p2m_access_t p2ma;
     struct p2m_domain *p2m = NULL;
 
-    ret = hvm_hap_nested_page_fault(gpa, 0, ~0ul, 
-                                    1, /* All NPFs count as reads */
-                                    npfec & PFEC_write_access, 
-                                    npfec & PFEC_insn_fetch);
+    struct npfec npfec = {
+        .read_access = 1, /* All NPFs count as reads */
+        .write_access = !!(pfec & PFEC_write_access),
+        .insn_fetch = !!(pfec & PFEC_insn_fetch)
+    };
+
+    ret = hvm_hap_nested_page_fault(gpa, ~0ul, npfec);
 
     if ( tb_init_done )
     {
@@ -1434,7 +1437,7 @@ static void svm_do_nested_pgfault(struct vcpu *v,
     case -1:
         ASSERT(nestedhvm_enabled(v->domain) && nestedhvm_vcpu_in_guestmode(v));
         /* inject #VMEXIT(NPF) into guest. */
-        nestedsvm_vmexit_defer(v, VMEXIT_NPF, npfec, gpa);
+        nestedsvm_vmexit_defer(v, VMEXIT_NPF, pfec, gpa);
         return;
     }
 

xen/arch/x86/hvm/vmx/vmx.c

@@ -2352,6 +2352,11 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
     p2m_type_t p2mt;
     int ret;
     struct domain *d = current->domain;
+    struct npfec npfec = {
+        .read_access = !!(qualification & EPT_READ_VIOLATION),
+        .write_access = !!(qualification & EPT_WRITE_VIOLATION),
+        .insn_fetch = !!(qualification & EPT_EXEC_VIOLATION)
+    };
 
     if ( tb_init_done )
     {
@@ -2370,14 +2375,14 @@ static void ept_handle_violation(unsigned long qualification, paddr_t gpa)
     }
 
     if ( qualification & EPT_GLA_VALID )
+    {
         __vmread(GUEST_LINEAR_ADDRESS, &gla);
+        npfec.gla_valid = 1;
+    }
     else
         gla = ~0ull;
-    ret = hvm_hap_nested_page_fault(gpa,
-                                    !!(qualification & EPT_GLA_VALID), gla,
-                                    !!(qualification & EPT_READ_VIOLATION),
-                                    !!(qualification & EPT_WRITE_VIOLATION),
-                                    !!(qualification & EPT_EXEC_VIOLATION));
+
+    ret = hvm_hap_nested_page_fault(gpa, gla, npfec);
     switch ( ret )
     {
     case 0:         // Unhandled L1 EPT violation

xen/arch/x86/mm/p2m.c

@@ -1323,9 +1323,9 @@ void p2m_mem_paging_resume(struct domain *d)
     }
 }
 
-bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla, 
-                          bool_t access_r, bool_t access_w, bool_t access_x,
-                          mem_event_request_t **req_ptr)
+bool_t p2m_mem_access_check(paddr_t gpa, unsigned long gla,
+                            struct npfec npfec,
+                            mem_event_request_t **req_ptr)
 {
     struct vcpu *v = current;
     unsigned long gfn = gpa >> PAGE_SHIFT;
@@ -1343,7 +1343,7 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla,
     gfn_lock(p2m, gfn, 0);
     mfn = p2m->get_entry(p2m, gfn, &p2mt, &p2ma, 0, NULL);
 
-    if ( access_w && p2ma == p2m_access_rx2rw ) 
+    if ( npfec.write_access && p2ma == p2m_access_rx2rw ) 
     {
         rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K, p2mt, p2m_access_rw);
         ASSERT(rc == 0);
@@ -1352,7 +1352,7 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla,
     }
     else if ( p2ma == p2m_access_n2rwx )
     {
-        ASSERT(access_w || access_r || access_x);
+        ASSERT(npfec.write_access || npfec.read_access || npfec.insn_fetch);
         rc = p2m->set_entry(p2m, gfn, mfn, PAGE_ORDER_4K,
                             p2mt, p2m_access_rwx);
         ASSERT(rc == 0);
@@ -1403,11 +1403,11 @@ bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla,
         /* Send request to mem event */
         req->gfn = gfn;
         req->offset = gpa & ((1 << PAGE_SHIFT) - 1);
-        req->gla_valid = gla_valid;
+        req->gla_valid = npfec.gla_valid;
         req->gla = gla;
-        req->access_r = access_r;
-        req->access_w = access_w;
-        req->access_x = access_x;
+        req->access_r = npfec.read_access;
+        req->access_w = npfec.write_access;
+        req->access_x = npfec.insn_fetch;
     
         req->vcpu_id = v->vcpu_id;
     }

xen/include/asm-x86/hvm/hvm.h

@@ -455,11 +455,8 @@ static inline void hvm_invalidate_regs_fields(struct cpu_user_regs *regs)
 #endif
 }
 
-int hvm_hap_nested_page_fault(paddr_t gpa,
-                              bool_t gla_valid, unsigned long gla,
-                              bool_t access_r,
-                              bool_t access_w,
-                              bool_t access_x);
+int hvm_hap_nested_page_fault(paddr_t gpa, unsigned long gla,
+                              struct npfec npfec);
 
 #define hvm_msr_tsc_aux(v) ({                                               \
     struct domain *__d = (v)->domain;                                       \

xen/include/asm-x86/mm.h

@@ -551,6 +551,16 @@ void audit_domains(void);
 
 #endif
 
+/*
+ * Nested page fault exception codes.
+ */
+struct npfec {
+    unsigned int read_access:1;
+    unsigned int write_access:1;
+    unsigned int insn_fetch:1;
+    unsigned int gla_valid:1;
+};
+
 int new_guest_cr3(unsigned long pfn);
 void make_cr3(struct vcpu *v, unsigned long mfn);
 void update_cr3(struct vcpu *v);

xen/include/asm-x86/p2m.h

@@ -597,9 +597,9 @@ void p2m_mem_paging_resume(struct domain *d);
  * been promoted with no underlying vcpu pause. If the req_ptr has been populated, 
  * then the caller must put the event in the ring (once having released get_gfn*
  * locks -- caller must also xfree the request. */
-bool_t p2m_mem_access_check(paddr_t gpa, bool_t gla_valid, unsigned long gla, 
-                          bool_t access_r, bool_t access_w, bool_t access_x,
-                          mem_event_request_t **req_ptr);
+bool_t p2m_mem_access_check(paddr_t gpa, unsigned long gla,
+                            struct npfec npfec,
+                            mem_event_request_t **req_ptr);
 /* Resumes the running of the VCPU, restarting the last instruction */
 void p2m_mem_access_resume(struct domain *d);