[xen staging] vVMX: adjust VMPTRLD error handling

[patchbot@xxxxxxx]

commit 25211747f5be293508dae80259e95b51e4af8171
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Wed Jun 4 12:12:40 2025 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Wed Jun 4 12:12:40 2025 +0200

    vVMX: adjust VMPTRLD error handling
    
    There are two issues there: When hvm_map_guest_frame_rw() yields a r/o
    page mapping, we fail to indicate the failure to the guest, and we fall
    over the NULL pointer in nvcpu->nv_vvmcx when subsequently invoking
    nvmx_set_vmcs_pointer() (if no earlier VMPTRLD put in place a valid
    value).
    
    Fixes: 5dbbaa0fe121 ("x86/vvmx: fix I/O and MSR bitmaps mapping")
    Reported-by: Manuel Andreas <manuel.andreas@xxxxxx>
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-By: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vvmx.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c
index ceb5e5a322..3c848ef546 100644
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -1820,7 +1820,8 @@ static int nvmx_handle_vmptrld(struct cpu_user_regs *regs)
                 vvmcx = NULL;
             }
         }
-        else
+
+        if ( !vvmcx )
         {
             vmfail(regs, VMX_INSN_VMPTRLD_INVALID_PHYADDR);
             goto out;
--
generated by git-patchbot for /home/xen/git/xen.git#staging