[xen staging-4.21] x86/domctl: restore all registers in arch_{get,set}_info_guest()

[patchbot@xxxxxxx]

commit d5ad2233bb43a6bdc84ccb2c9134bece2e2ec94c
Author:     Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
AuthorDate: Mon Jul 20 13:30:52 2026 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon Jul 20 13:30:52 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>
    master commit: bedbc17d8407c456c7fbe126c0df55610559d8c6
    master date: 2026-07-20 11:11:37 +0200
---
 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 9af833b6da..893ebaa13a 100644
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1280,6 +1280,14 @@ 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 b8bc0caaf2..40f4cb049c 100644
--- a/xen/arch/x86/domctl.c
+++ b/xen/arch/x86/domctl.c
@@ -1440,6 +1440,14 @@ 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#staging-4.21