[PATCH 1/3] target/i386: allow modifying TCG phys-addr-bits

[Paolo Bonzini <pbonzini@redhat.com>]

TCG can support any number of physical address bits as long as the
core memory API does.  We only need to compute the reserved bits
mask dynamically.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 target/i386/cpu.c             | 23 ++++++++---------------
 target/i386/cpu.h             |  1 -
 target/i386/tcg/excp_helper.c |  7 ++++---
 target/i386/tcg/helper-tcg.h  | 12 ++++--------
 4 files changed, 16 insertions(+), 27 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index ae9fd9f31d..6b3e9467f1 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -6785,21 +6785,14 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
                     cpu->phys_bits = cpu->host_phys_bits_limit;
                 }
             }
-
-            if (cpu->phys_bits &&
-                (cpu->phys_bits > TARGET_PHYS_ADDR_SPACE_BITS ||
-                cpu->phys_bits < 32)) {
-                error_setg(errp, "phys-bits should be between 32 and %u "
-                                 " (but is %u)",
-                                 TARGET_PHYS_ADDR_SPACE_BITS, cpu->phys_bits);
-                return;
-            }
-        } else {
-            if (cpu->phys_bits && cpu->phys_bits != TCG_PHYS_ADDR_BITS) {
-                error_setg(errp, "TCG only supports phys-bits=%u",
-                                  TCG_PHYS_ADDR_BITS);
-                return;
-            }
+        }
+        if (cpu->phys_bits &&
+            (cpu->phys_bits > TARGET_PHYS_ADDR_SPACE_BITS ||
+            cpu->phys_bits < 32)) {
+            error_setg(errp, "phys-bits should be between 32 and %u "
+                             " (but is %u)",
+                             TARGET_PHYS_ADDR_SPACE_BITS, cpu->phys_bits);
+            return;
         }
         /* 0 means it was not explicitly set by the user (or by machine
          * compat_props or by the host code above). In this case, the default
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index b4b136cd0d..570f916878 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -290,7 +290,6 @@ typedef enum X86Seg {
 #define PG_GLOBAL_MASK   (1 << PG_GLOBAL_BIT)
 #define PG_PSE_PAT_MASK  (1 << PG_PSE_PAT_BIT)
 #define PG_ADDRESS_MASK  0x000ffffffffff000LL
-#define PG_HI_RSVD_MASK  (PG_ADDRESS_MASK & ~PHYS_ADDR_MASK)
 #define PG_HI_USER_MASK  0x7ff0000000000000LL
 #define PG_PKRU_MASK     (15ULL << PG_PKRU_BIT)
 #define PG_NX_MASK       (1ULL << PG_NX_BIT)
diff --git a/target/i386/tcg/excp_helper.c b/target/i386/tcg/excp_helper.c
index b7d6259e4a..1e71e44510 100644
--- a/target/i386/tcg/excp_helper.c
+++ b/target/i386/tcg/excp_helper.c
@@ -142,8 +142,9 @@ void raise_exception_ra(CPUX86State *env, int exception_index, uintptr_t retaddr
 static hwaddr get_hphys(CPUState *cs, hwaddr gphys, MMUAccessType access_type,
                         int *prot)
 {
-    CPUX86State *env = &X86_CPU(cs)->env;
-    uint64_t rsvd_mask = PG_HI_RSVD_MASK;
+    X86CPU *cpu = X86_CPU(cs);
+    CPUX86State *env = &cpu->env;
+    uint64_t rsvd_mask = PG_ADDRESS_MASK & ~MAKE_64BIT_MASK(0, cpu->phys_bits);
     uint64_t ptep, pte;
     uint64_t exit_info_1 = 0;
     target_ulong pde_addr, pte_addr;
@@ -358,7 +359,7 @@ static int handle_mmu_fault(CPUState *cs, vaddr addr, int size,
     int error_code = 0;
     int is_dirty, prot, page_size, is_write, is_user;
     hwaddr paddr;
-    uint64_t rsvd_mask = PG_HI_RSVD_MASK;
+    uint64_t rsvd_mask = PG_ADDRESS_MASK & ~MAKE_64BIT_MASK(0, cpu->phys_bits);
     uint32_t page_offset;
     target_ulong vaddr;
     uint32_t pkr;
diff --git a/target/i386/tcg/helper-tcg.h b/target/i386/tcg/helper-tcg.h
index c133c63555..ef60e2e04b 100644
--- a/target/i386/tcg/helper-tcg.h
+++ b/target/i386/tcg/helper-tcg.h
@@ -25,17 +25,13 @@
 /* Maximum instruction code size */
 #define TARGET_MAX_INSN_SIZE 16
 
-/*
- * XXX: This value should match the one returned by CPUID
- * and in exec.c
- */
-# if defined(TARGET_X86_64)
+#if defined(TARGET_X86_64)
 # define TCG_PHYS_ADDR_BITS 40
-# else
+#else
 # define TCG_PHYS_ADDR_BITS 36
-# endif
+#endif
 
-#define PHYS_ADDR_MASK MAKE_64BIT_MASK(0, TCG_PHYS_ADDR_BITS)
+QEMU_BUILD_BUG_ON(TCG_PHYS_ADDR_BITS > TARGET_PHYS_ADDR_SPACE_BITS);
 
 /**
  * x86_cpu_do_interrupt:
-- 
2.26.2