x86/xen: Add xen_no_vector_callback option to test PCI INTX delivery

[ Upstream commit b36b0fe96af13460278bf9b173beced1bd15f85d ]

It's useful to be able to test non-vector event channel delivery, to make
sure Linux will work properly on older Xen which doesn't have it.

It's also useful for those working on Xen and Xen-compatible hypervisors,
because there are guest kernels still in active use which use PCI INTX
even when vector delivery is available.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/20210106153958.584169-4-dwmw2@infradead.org
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
David Woodhouse 2021-01-06 15:39:56 +00:00 committed by Greg Kroah-Hartman
parent a09d4e7acd
commit 5fa6987258
2 changed files with 14 additions and 1 deletions

View File

@ -5452,6 +5452,10 @@
This option is obsoleted by the "nopv" option, which
has equivalent effect for XEN platform.
xen_no_vector_callback
[KNL,X86,XEN] Disable the vector callback for Xen
event channel interrupts.
xen_scrub_pages= [XEN]
Boolean option to control scrubbing pages before giving them back
to Xen, for use by other domains. Can be also changed at runtime

View File

@ -175,6 +175,8 @@ static int xen_cpu_dead_hvm(unsigned int cpu)
return 0;
}
static bool no_vector_callback __initdata;
static void __init xen_hvm_guest_init(void)
{
if (xen_pv_domain())
@ -194,7 +196,7 @@ static void __init xen_hvm_guest_init(void)
xen_panic_handler_init();
if (xen_feature(XENFEAT_hvm_callback_vector))
if (!no_vector_callback && xen_feature(XENFEAT_hvm_callback_vector))
xen_have_vector_callback = 1;
xen_hvm_smp_init();
@ -220,6 +222,13 @@ static __init int xen_parse_nopv(char *arg)
}
early_param("xen_nopv", xen_parse_nopv);
static __init int xen_parse_no_vector_callback(char *arg)
{
no_vector_callback = true;
return 0;
}
early_param("xen_no_vector_callback", xen_parse_no_vector_callback);
bool __init xen_hvm_need_lapic(void)
{
if (xen_pv_domain())