[xen master] x86: avoid Misra Rule 19.1 violations

[patchbot@xxxxxxx]

commit 7225f13aef0316f0c1e5d8d36b012ba5f3f19327
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Aug 1 11:47:38 2023 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Aug 1 11:47:38 2023 +0200

    x86: avoid Misra Rule 19.1 violations
    
    Not exactly overlapping accesses to objects on the left and right hand
    sides of an assignment are generally UB, and hence disallowed by Misra.
    While in the specific cases we're talking about here no actual UB can
    result as long as the compiler doesn't act actively "maliciously", let's
    still switch to using casts combined with exactly overlapping accesses.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/hvm.c                 |  2 +-
 xen/arch/x86/hvm/svm/svm.c             |  2 +-
 xen/arch/x86/hvm/vmx/vmx.c             |  2 +-
 xen/arch/x86/x86_emulate/x86_emulate.c | 10 +++++-----
 4 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
index 0e471e02a1..2180abeb33 100644
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -3861,7 +3861,7 @@ void hvm_ud_intercept(struct cpu_user_regs *regs)
 
             /* Zero the upper 32 bits of %rip if not in 64bit mode. */
             if ( !(hvm_long_mode_active(cur) && cs->l) )
-                regs->rip = regs->eip;
+                regs->rip = (uint32_t)regs->rip;
 
             add_taint(TAINT_HVM_FEP);
 
diff --git a/xen/arch/x86/hvm/svm/svm.c b/xen/arch/x86/hvm/svm/svm.c
index 56cb2f61bb..27170213ae 100644
--- a/xen/arch/x86/hvm/svm/svm.c
+++ b/xen/arch/x86/hvm/svm/svm.c
@@ -1420,7 +1420,7 @@ static void cf_check svm_inject_event(const struct 
x86_event *event)
      */
     if ( !((vmcb_get_efer(vmcb) & EFER_LMA) && vmcb->cs.l) )
     {
-        regs->rip = regs->eip;
+        regs->rip = (uint32_t)regs->rip;
         vmcb->nextrip = (uint32_t)vmcb->nextrip;
     }
 
diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index c686e6990c..7ec44018d4 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -4760,7 +4760,7 @@ out:
                 regs->rip = (long)(regs->rip << (64 - VADDR_BITS)) >>
                             (64 - VADDR_BITS);
             else
-                regs->rip = regs->eip;
+                regs->rip = (uint32_t)regs->rip;
         }
         else
             domain_crash(v->domain);
diff --git a/xen/arch/x86/x86_emulate/x86_emulate.c 
b/xen/arch/x86/x86_emulate/x86_emulate.c
index 60bd2f8d8e..e88245eae9 100644
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -503,8 +503,8 @@ static inline void put_loop_count(
         if ( mode_64bit() && ad_bytes == 4 )                            \
         {                                                               \
             _regs.r(cx) = 0;                                            \
-            if ( using_si ) _regs.r(si) = _regs.esi;                    \
-            if ( using_di ) _regs.r(di) = _regs.edi;                    \
+            if ( using_si ) _regs.r(si) = (uint32_t)_regs.r(si);        \
+            if ( using_di ) _regs.r(di) = (uint32_t)_regs.r(di);        \
         }                                                               \
         goto complete_insn;                                             \
     }                                                                   \
@@ -1984,9 +1984,9 @@ x86_emulate(
     case 0x98: /* cbw/cwde/cdqe */
         switch ( op_bytes )
         {
-        case 2: _regs.ax = (int8_t)_regs.al; break; /* cbw */
+        case 2: _regs.ax = (int8_t)_regs.ax; break; /* cbw */
         case 4: _regs.r(ax) = (uint32_t)(int16_t)_regs.ax; break; /* cwde */
-        case 8: _regs.r(ax) = (int32_t)_regs.eax; break; /* cdqe */
+        case 8: _regs.r(ax) = (int32_t)_regs.r(ax); break; /* cdqe */
         }
         break;
 
@@ -8377,7 +8377,7 @@ x86_emulate(
 
     /* Zero the upper 32 bits of %rip if not in 64-bit mode. */
     if ( !mode_64bit() )
-        _regs.r(ip) = _regs.eip;
+        _regs.r(ip) = (uint32_t)_regs.r(ip);
 
     /* Should a singlestep #DB be raised? */
     if ( rc == X86EMUL_OKAY && singlestep && !ctxt->retire.mov_ss )
--
generated by git-patchbot for /home/xen/git/xen.git#master