Re: [PATCH] x86/svm: mandatory update VMCB nextrip for soft interrupts

Jan Beulich <[email protected]> Thu, 6 Aug 2026 08:14:10 +0200
Newsgroups gmane.comp.emulators.xen.devel
Message-ID <[email protected]>
On 06.08.2026 05:17, Chunjie Zhu wrote:
> Signed-off-by: Chunjie Zhu <[email protected]>
> ---
>  xen/arch/x86/hvm/svm/nestedsvm.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

Several (formal) issues: First, please adhere to patch submission guidelines:
To: the list, with maintainers Cc:-ed.

> --- a/xen/arch/x86/hvm/svm/nestedsvm.c
> +++ b/xen/arch/x86/hvm/svm/nestedsvm.c
> @@ -449,7 +449,14 @@ static int nsvm_vmcb_prepare4vmrun(struct vcpu *v, struct cpu_user_regs *regs)
>      n2vmcb->virt_ext.bytes =
>          n1vmcb->virt_ext.bytes | ns_vmcb->virt_ext.bytes;
>  
> -    /* NextRIP - only evaluated on #VMEXIT. */
> +    /* next_rip is consumed on VMRUN as the return address pushed on the
> +     * stack·for·injected·soft·exceptions/interrupts. This assignment
> +     * statement must be enforced, otherwise, it might cause vcpu wedge.
> +     *
> +     * APM Vol.2 Event Injection does not specifies what happens if NEXTRIP
> +     * holds an invalid/garbage value.
> +     */
> +    n2vmcb->nextrip = ns_vmcb->nextrip;

Then, much of the comment looks like it wants to be the patch description
instead. Any remaining comment here then wants to follow style as set forth
by ./CODING_STYLE. And finally the unusual not-exactly-space characters
('·') likely aren't justified to use here.

Jan