[PATCH 2/2] xen/x86: address violations of Rule 11.3

[<victorm.lira@xxxxxxx>]

From: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>

Use {get,put}_unaligned_t to ensure that reads and writes are
safe to perform even on potentially misaligned pointers.

Signed-off-by: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Signed-off-by: Victor Lira <victorm.lira@xxxxxxx>
---
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Anthony PERARD <anthony.perard@xxxxxxxxxx>
Cc: Michal Orzel <michal.orzel@xxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Julien Grall <julien@xxxxxxx>
Cc: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Nicola Vetrini <nicola.vetrini@xxxxxxxxxxx>
Cc: Federico Serafini <federico.serafini@xxxxxxxxxxx>
Cc: Bertrand Marquis <bertrand.marquis@xxxxxxx>
---
 xen/arch/x86/alternative.c               | 12 ++++++++----
 xen/arch/x86/hvm/emulate.c               |  8 ++++----
 xen/arch/x86/include/asm/hvm/vlapic.h    |  5 +++--
 xen/arch/x86/setup.c                     |  2 +-
 xen/drivers/passthrough/amd/iommu_init.c |  2 +-
 5 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/xen/arch/x86/alternative.c b/xen/arch/x86/alternative.c
index d4fe56b3da..200cf2e44c 100644
--- a/xen/arch/x86/alternative.c
+++ b/xen/arch/x86/alternative.c
@@ -17,6 +17,7 @@
 #include <asm/nmi.h>
 #include <asm/nops.h>
 #include <xen/livepatch.h>
+#include <xen/unaligned.h>

 #define MAX_PATCH_LEN (255-1)

@@ -168,7 +169,7 @@ void *place_ret(void *ptr)
         BUG_ON((int32_t)disp != disp);

         *p++ = 0xe9;
-        *(int32_t *)p = disp;
+        put_unaligned_t(int32_t, disp, p);
         p += 4;
     }
     else
@@ -345,8 +346,11 @@ static int init_or_livepatch _apply_alternatives(struct 
alt_instr *start,

         /* 0xe8/0xe9 are relative branches; fix the offset. */
         if ( a->repl_len >= 5 && (*buf & 0xfe) == 0xe8 )
-            *(int32_t *)(buf + 1) += repl - orig;
+        {
+            int32_t val = get_unaligned_t(int32_t, buf + 1);

+            put_unaligned_t(int32_t, val + repl - orig, buf + 1);
+        }
         a->priv = 1;

         add_nops(buf + a->repl_len, total_len - a->repl_len);
@@ -388,7 +392,7 @@ static int init_or_livepatch apply_alt_calls(
             return -EINVAL;
         }

-        disp = *(int32_t *)(orig + 2);
+        disp = get_unaligned_t(int32_t, orig + 2);
         dest = *(const void **)(orig + 6 + disp);

         if ( dest )
@@ -420,7 +424,7 @@ static int init_or_livepatch apply_alt_calls(

             buf[0] = 0x2e;
             buf[1] = 0xe8;
-            *(int32_t *)(buf + 2) = disp;
+            put_unaligned_t(int32_t, disp, buf + 2);
         }
         else
         {
diff --git a/xen/arch/x86/hvm/emulate.c b/xen/arch/x86/hvm/emulate.c
index 91f004d233..3b644eed12 100644
--- a/xen/arch/x86/hvm/emulate.c
+++ b/xen/arch/x86/hvm/emulate.c
@@ -68,17 +68,17 @@ static void hvmtrace_io_assist(const ioreq_t *p)
     else
         event = p->dir ? TRC_HVM_IOPORT_READ : TRC_HVM_IOPORT_WRITE;

-    *(uint64_t *)buffer = p->addr;
-    size = (p->addr != (u32)p->addr) ? 8 : 4;
+    put_unaligned_t(uint64_t, p->addr, buffer);
+    size = (p->addr != (uint32_t)p->addr) ? 8 : 4;
     if ( size == 8 )
         event |= TRC_64_FLAG;

     if ( !p->data_is_ptr )
     {
         if ( size == 4 )
-            *(uint32_t *)&buffer[size] = p->data;
+            put_unaligned_t(uint32_t, p->data, &buffer[size]);
         else
-            *(uint64_t *)&buffer[size] = p->data;
+            put_unaligned_t(uint64_t, p->data, &buffer[size]);
         size *= 2;
     }

diff --git a/xen/arch/x86/include/asm/hvm/vlapic.h 
b/xen/arch/x86/include/asm/hvm/vlapic.h
index c388551198..c7a26c0a0f 100644
--- a/xen/arch/x86/include/asm/hvm/vlapic.h
+++ b/xen/arch/x86/include/asm/hvm/vlapic.h
@@ -10,6 +10,7 @@
 #define __ASM_X86_HVM_VLAPIC_H__

 #include <xen/tasklet.h>
+#include <xen/unaligned.h>
 #include <asm/hvm/vpt.h>

 #define vcpu_vlapic(x)   (&(x)->arch.hvm.vlapic)
@@ -85,13 +86,13 @@ struct vlapic {
 static inline uint32_t vlapic_get_reg(const struct vlapic *vlapic,
                                       uint32_t reg)
 {
-    return *((uint32_t *)(&vlapic->regs->data[reg]));
+    return get_unaligned_t(uint32_t, &vlapic->regs->data[reg]);
 }

 static inline void vlapic_set_reg(
     struct vlapic *vlapic, uint32_t reg, uint32_t val)
 {
-    *((uint32_t *)(&vlapic->regs->data[reg])) = val;
+    put_unaligned_t(uint32_t, val, &vlapic->regs->data[reg]);
 }

 void vlapic_reg_write(struct vcpu *v, unsigned int reg, uint32_t val);
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c
index 1f5cb67bd0..5919e94f5b 100644
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -1249,7 +1249,7 @@ void asmlinkage __init noreturn __start_xen(void)
                (caps & 2) ? " V2" : "",
                !(caps & 3) ? " none" : "");
         printk("EDID transfer time: %d seconds\n", caps >> 8);
-        if ( *(u32 *)bootsym(boot_edid_info) == 0x13131313 )
+        if ( get_unaligned_t(u32, bootsym(boot_edid_info)) == 0x13131313 )
         {
             printk(" EDID info not retrieved because ");
             if ( !(caps & 3) )
diff --git a/xen/drivers/passthrough/amd/iommu_init.c 
b/xen/drivers/passthrough/amd/iommu_init.c
index bb25b55c85..c00aa64983 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -562,7 +562,7 @@ static void cf_check parse_event_log_entry(struct amd_iommu 
*iommu, u32 entry[])
         unsigned int device_id = MASK_EXTR(entry[0], 
IOMMU_EVENT_DEVICE_ID_MASK);
         unsigned int domain_id = MASK_EXTR(entry[1], 
IOMMU_EVENT_DOMAIN_ID_MASK);
         unsigned int flags = MASK_EXTR(entry[1], IOMMU_EVENT_FLAGS_MASK);
-        uint64_t addr = *(uint64_t *)(entry + 2);
+        uint64_t addr = get_unaligned_t(uint64_t, entry + 2);

         printk(XENLOG_ERR "AMD-Vi: %s: %pp d%u addr %016"PRIx64
                " flags %#x%s%s%s%s%s%s%s%s%s%s\n",
--
2.25.1