[xen stable-4.22] x86/domctl: restore all registers in arch_{get,set}_info_guest()

[patchbot@xxxxxxx]

commit 2a36c6edc9e90d5b0287ba54cd8ad7e611ea055d
Author:     Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Jul 20 11:11:37 2026 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 20 12:31:16 2026 +0200

    x86/domctl: restore all registers in arch_{get,set}_info_guest()
    
    Commit 9f892f84c279 ("x86/domctl: Stop using XLAT_cpu_user_regs()")
    converted memcpy() of the cpu_user_regs structure to explicit copy of
    its fields. In the compat case, it intentionally missed few of them,
    named in the commit message. But the 64bit case missed also r8-r15
    registers, which was not intentional. This, at least, caused Linux
    6.18.x crash when resuming PVH domU.
    
    Fix it by adding missing assignments.
    
    Fixes: 9f892f84c279 ("x86/domctl: Stop using XLAT_cpu_user_regs()")
    Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Teddy Astie <teddy.astie@xxxxxxxxxx>
    Release-acked-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/x86/domain.c | 8 ++++++++
 xen/arch/x86/domctl.c | 8 ++++++++
 2 files changed, 16 insertions(+)

diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
index 1d458f1372..ba7244ccc5 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1255,6 +1255,14 @@ int arch_set_info_guest(
 
     if ( !compat )
     {
+        v->arch.user_regs.r15               = c.nat->user_regs.r15;
+        v->arch.user_regs.r14               = c.nat->user_regs.r14;
+        v->arch.user_regs.r13               = c.nat->user_regs.r13;
+        v->arch.user_regs.r12               = c.nat->user_regs.r12;
+        v->arch.user_regs.r11               = c.nat->user_regs.r11;
+        v->arch.user_regs.r10               = c.nat->user_regs.r10;
+        v->arch.user_regs.r9                = c.nat->user_regs.r9;
+        v->arch.user_regs.r8                = c.nat->user_regs.r8;
         v->arch.user_regs.rbx               = c.nat->user_regs.rbx;
         v->arch.user_regs.rcx               = c.nat->user_regs.rcx;
         v->arch.user_regs.rdx               = c.nat->user_regs.rdx;
diff --git a/xen/arch/x86/domctl.c b/xen/arch/x86/domctl.c
index 07f712a0a4..3ea4c650ee 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1481,6 +1481,14 @@ void arch_get_info_guest(struct vcpu *v, 
vcpu_guest_context_u c)
     if ( !compat )
     {
         /* Backing memory is pre-zeroed. */
+        c.nat->user_regs.r15               = v->arch.user_regs.r15;
+        c.nat->user_regs.r14               = v->arch.user_regs.r14;
+        c.nat->user_regs.r13               = v->arch.user_regs.r13;
+        c.nat->user_regs.r12               = v->arch.user_regs.r12;
+        c.nat->user_regs.r11               = v->arch.user_regs.r11;
+        c.nat->user_regs.r10               = v->arch.user_regs.r10;
+        c.nat->user_regs.r9                = v->arch.user_regs.r9;
+        c.nat->user_regs.r8                = v->arch.user_regs.r8;
         c.nat->user_regs.rbx               = v->arch.user_regs.rbx;
         c.nat->user_regs.rcx               = v->arch.user_regs.rcx;
         c.nat->user_regs.rdx               = v->arch.user_regs.rdx;
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.22