File xsa456-0p.patch of Package xen.33625

# Commit 45dac88e78e8a2d9d8738eef884fe6730faf9e67
# Date 2024-04-09 16:37:30 +0100
# Author Andrew Cooper <andrew.cooper3@citrix.com>
# Committer Andrew Cooper <andrew.cooper3@citrix.com>
x86/spec-ctrl: Widen the {xen,last,default}_spec_ctrl fields

Right now, they're all bytes, but MSR_SPEC_CTRL has been steadily gaining new
features.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>

--- a/xen/arch/x86/hvm/svm/entry.S
+++ b/xen/arch/x86/hvm/svm/entry.S
@@ -65,14 +65,14 @@ __UNLIKELY_END(nsvm_hap)
         /* SPEC_CTRL_EXIT_TO_SVM       Req: b=curr %rsp=regs/cpuinfo, Clob: acd */
         .macro svm_vmentry_spec_ctrl
             mov    VCPU_arch_msrs(%rbx), %rax
-            movzbl CPUINFO_last_spec_ctrl(%rsp), %edx
+            mov    CPUINFO_last_spec_ctrl(%rsp), %edx
             mov    VCPUMSR_spec_ctrl_raw(%rax), %eax
             cmp    %edx, %eax
             je     1f /* Skip write if value is correct. */
             mov    $MSR_SPEC_CTRL, %ecx
             xor    %edx, %edx
             wrmsr
-            mov    %al, CPUINFO_last_spec_ctrl(%rsp)
+            mov    %eax, CPUINFO_last_spec_ctrl(%rsp)
 1:          /* No Spectre v1 concerns.  Execution will hit VMRUN imminently. */
         .endm
         ALTERNATIVE "", svm_vmentry_spec_ctrl, X86_FEATURE_SC_MSR_HVM
@@ -132,14 +132,14 @@ __UNLIKELY_END(nsvm_hap)
          * safe to use.  The guest's setting resides in the VMCB.
          */
         .macro svm_vmexit_spec_ctrl
-            movzbl CPUINFO_xen_spec_ctrl(%rsp), %eax
-            movzbl CPUINFO_last_spec_ctrl(%rsp), %edx
+            mov    CPUINFO_xen_spec_ctrl(%rsp), %eax
+            mov    CPUINFO_last_spec_ctrl(%rsp), %edx
             cmp    %edx, %eax
             je     1f /* Skip write if value is correct. */
             mov    $MSR_SPEC_CTRL, %ecx
             xor    %edx, %edx
             wrmsr
-            mov    %al, CPUINFO_last_spec_ctrl(%rsp)
+            mov    %eax, CPUINFO_last_spec_ctrl(%rsp)
 1:
         .endm
         ALTERNATIVE "", svm_vmexit_spec_ctrl, X86_FEATURE_SC_MSR_HVM
--- a/xen/arch/x86/hvm/vmx/entry.S
+++ b/xen/arch/x86/hvm/vmx/entry.S
@@ -52,7 +52,7 @@ ENTRY(vmx_asm_vmexit_handler)
          */
         .macro restore_spec_ctrl
             mov    $MSR_SPEC_CTRL, %ecx
-            movzbl CPUINFO_xen_spec_ctrl(%rsp), %eax
+            mov    CPUINFO_xen_spec_ctrl(%rsp), %eax
             xor    %edx, %edx
             wrmsr
         .endm
--- a/xen/arch/x86/spec_ctrl.c
+++ b/xen/arch/x86/spec_ctrl.c
@@ -66,7 +66,7 @@ bool __read_mostly opt_branch_harden = t
 static bool __initdata opt_lock_harden;
 
 bool __initdata bsp_delay_spec_ctrl;
-uint8_t __read_mostly default_xen_spec_ctrl;
+unsigned int __read_mostly default_xen_spec_ctrl;
 uint8_t __read_mostly default_scf;
 
 paddr_t __read_mostly l1tf_addr_mask, __read_mostly l1tf_safe_maddr;
--- a/xen/include/asm-x86/current.h
+++ b/xen/include/asm-x86/current.h
@@ -55,8 +55,8 @@ struct cpu_info {
 
     /* See asm-x86/spec_ctrl_asm.h for usage. */
     unsigned int shadow_spec_ctrl;
-    uint8_t      xen_spec_ctrl;
-    uint8_t      last_spec_ctrl;
+    unsigned int xen_spec_ctrl;
+    unsigned int last_spec_ctrl;
     uint8_t      scf; /* SCF_* */
 
     /*
--- a/xen/include/asm-x86/spec_ctrl.h
+++ b/xen/include/asm-x86/spec_ctrl.h
@@ -94,7 +94,7 @@ extern int8_t opt_l1d_flush;
 extern bool opt_branch_harden;
 
 extern bool bsp_delay_spec_ctrl;
-extern uint8_t default_xen_spec_ctrl;
+extern unsigned int default_xen_spec_ctrl;
 extern uint8_t default_scf;
 
 extern int8_t opt_xpti_hwdom, opt_xpti_domu;
--- a/xen/include/asm-x86/spec_ctrl_asm.h
+++ b/xen/include/asm-x86/spec_ctrl_asm.h
@@ -217,10 +217,10 @@
         setnz %al
         not %eax
         and %al, STACK_CPUINFO_FIELD(scf)(%r14)
-        movzbl STACK_CPUINFO_FIELD(xen_spec_ctrl)(%r14), %eax
+        mov STACK_CPUINFO_FIELD(xen_spec_ctrl)(%r14), %eax
     .else
         andb $~SCF_use_shadow, CPUINFO_scf(%rsp)
-        movzbl CPUINFO_xen_spec_ctrl(%rsp), %eax
+        mov  CPUINFO_xen_spec_ctrl(%rsp), %eax
     .endif
 
     wrmsr
@@ -418,7 +418,7 @@
 
     /* Load Xen's intended value. */
     mov $MSR_SPEC_CTRL, %ecx
-    movzbl STACK_CPUINFO_FIELD(xen_spec_ctrl)(%r14), %eax
+    mov STACK_CPUINFO_FIELD(xen_spec_ctrl)(%r14), %eax
     wrmsr
 
 .L\@_skip_msr_spec_ctrl: