pseries: More complete WIMG validation in H_ENTER code

Currently our implementation of the H_ENTER hypercall, which inserts a
mapping in the hash page table assumes that only ordinary memory is ever
mapped, and only permits mapping attribute bits accordingly (WIMG==0010).

However, we intend to start adding emulated IO to the pseries platform
(and real IO with PCI passthrough on kvm) which means this simple test
will no longer suffice.

This patch extends the h_enter validation code to check if the given
address is a RAM address.  If it is it enforces WIMG==0010, otherwise
it assumes that it is an IO mapping and instead enforces WIMG=010x.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alexander Graf <agraf@suse.de>

1 files changed, 18 insertions, 4 deletions

diff --git a/hw/spapr_hcall.c b/hw/spapr_hcall.c
index f7ead04a96..70f853cb1b 100644
--- a/hw/spapr_hcall.c
+++ b/hw/spapr_hcall.c
@@ -99,6 +99,8 @@ static target_ulong h_enter(CPUState *env, sPAPREnvironment *spapr,
     target_ulong pte_index = args[1];
     target_ulong pteh = args[2];
     target_ulong ptel = args[3];
+    target_ulong page_shift = 12;
+    target_ulong raddr;
     target_ulong i;
     uint8_t *hpte;
 
@@ -111,6 +113,7 @@ static target_ulong h_enter(CPUState *env, sPAPREnvironment *spapr,
 #endif
         if ((ptel & 0xff000) == 0) {
             /* 16M page */
+            page_shift = 24;
             /* lowest AVA bit must be 0 for 16M pages */
             if (pteh & 0x80) {
                 return H_PARAMETER;
@@ -120,12 +123,23 @@ static target_ulong h_enter(CPUState *env, sPAPREnvironment *spapr,
         }
     }
 
-    /* FIXME: bounds check the pa? */
+    raddr = (ptel & HPTE_R_RPN) & ~((1ULL << page_shift) - 1);
 
-    /* Check WIMG */
-    if ((ptel & HPTE_R_WIMG) != HPTE_R_M) {
-        return H_PARAMETER;
+    if (raddr < spapr->ram_limit) {
+        /* Regular RAM - should have WIMG=0010 */
+        if ((ptel & HPTE_R_WIMG) != HPTE_R_M) {
+            return H_PARAMETER;
+        }
+    } else {
+        /* Looks like an IO address */
+        /* FIXME: What WIMG combinations could be sensible for IO?
+         * For now we allow WIMG=010x, but are there others? */
+        /* FIXME: Should we check against registered IO addresses? */
+        if ((ptel & (HPTE_R_W | HPTE_R_I | HPTE_R_M)) != HPTE_R_I) {
+            return H_PARAMETER;
+        }
     }
+
     pteh &= ~0x60ULL;
 
     if ((pte_index * HASH_PTE_SIZE_64) & ~env->htab_mask) {