[Qemu-devel] [PATCH 3/5] linux-user: Allocate guest-reachable descriptor tables

[Jan Kiszka <jan.kiszka@web.de>]

IDT, GDT and LDTs have to allocated from memory regions also reachable
by the guests. Obtain them via the new qemu_vmalloc_guest_safe service.

Signed-off-by: Jan Kiszka <jan.kiszka@web.de>
---
 linux-user/i386/syscall.h   |    2 ++
 linux-user/main.c           |   13 +++++++------
 linux-user/syscall.c        |    3 ++-
 linux-user/x86_64/syscall.h |    2 ++
 4 files changed, 13 insertions(+), 7 deletions(-)

Index: b/linux-user/main.c
===================================================================
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -280,9 +280,9 @@ static void write_dt(void *ptr, unsigned
     p[1] = tswapl(e2);
 }
 
-#if TARGET_X86_64
-uint64_t idt_table[512];
+uint64_t *idt_table;
 
+#if TARGET_X86_64
 static void set_gate64(void *ptr, unsigned int type, unsigned int dpl,
                        uint64_t addr, unsigned int sel)
 {
@@ -301,8 +301,6 @@ static void set_idt(int n, unsigned int
     set_gate64(idt_table + n * 2, 0, dpl, 0, 0);
 }
 #else
-uint64_t idt_table[256];
-
 static void set_gate(void *ptr, unsigned int type, unsigned int dpl,
                      uint32_t addr, unsigned int sel)
 {
@@ -2444,8 +2442,10 @@ int main(int argc, char **argv)
 #endif
 
     /* linux interrupt setup */
+    idt_table = qemu_vmalloc_guest_safe(sizeof(uint64_t) * TARGET_IDT_ENTRIES);
+    memset(idt_table, 0, sizeof(uint64_t) * TARGET_IDT_ENTRIES);
     env->idt.base = h2g(idt_table);
-    env->idt.limit = sizeof(idt_table) - 1;
+    env->idt.limit = sizeof(uint64_t) * TARGET_IDT_ENTRIES - 1;
     set_idt(0, 0);
     set_idt(1, 0);
     set_idt(2, 0);
@@ -2471,7 +2471,8 @@ int main(int argc, char **argv)
     /* linux segment setup */
     {
         uint64_t *gdt_table;
-        gdt_table = qemu_mallocz(sizeof(uint64_t) * TARGET_GDT_ENTRIES);
+        gdt_table = qemu_vmalloc_guest_safe(sizeof(uint64_t) * TARGET_GDT_ENTRIES);
+        memset(gdt_table, 0, sizeof(uint64_t) * TARGET_GDT_ENTRIES);
         env->gdt.base = h2g((unsigned long)gdt_table);
         env->gdt.limit = sizeof(uint64_t) * TARGET_GDT_ENTRIES - 1;
 #ifdef TARGET_ABI32
Index: b/linux-user/i386/syscall.h
===================================================================
--- a/linux-user/i386/syscall.h
+++ b/linux-user/i386/syscall.h
@@ -22,6 +22,8 @@ struct target_pt_regs {
 
 /* ioctls */
 
+#define TARGET_IDT_ENTRIES      256
+
 #define TARGET_LDT_ENTRIES      8192
 #define TARGET_LDT_ENTRY_SIZE	8
 
Index: b/linux-user/x86_64/syscall.h
===================================================================
--- a/linux-user/x86_64/syscall.h
+++ b/linux-user/x86_64/syscall.h
@@ -29,6 +29,8 @@ struct target_pt_regs {
 /* top of stack page */
 };
 
+#define TARGET_IDT_ENTRIES      512
+
 /* Maximum number of LDT entries supported. */
 #define TARGET_LDT_ENTRIES	8192
 /* The size of each LDT entry. */
Index: b/linux-user/syscall.c
===================================================================
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -2474,7 +2474,8 @@ static abi_long write_ldt(CPUX86State *e
     }
     /* allocate the LDT */
     if (!ldt_table) {
-        ldt_table = malloc(TARGET_LDT_ENTRIES * TARGET_LDT_ENTRY_SIZE);
+        ldt_table = qemu_vmalloc_guest_safe(TARGET_LDT_ENTRIES
+                                            * TARGET_LDT_ENTRY_SIZE);
         if (!ldt_table)
             return -TARGET_ENOMEM;
         memset(ldt_table, 0, TARGET_LDT_ENTRIES * TARGET_LDT_ENTRY_SIZE);