From: David Woodhouse dwmw@amazon.co.uk
[ 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 --- Documentation/admin-guide/kernel-parameters.txt | 4 ++++ arch/x86/xen/enlighten_hvm.c | 11 ++++++++++- 2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index f6a1513dfb76c..26bfe7ae711b8 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5965,6 +5965,10 @@ 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 diff --git a/arch/x86/xen/enlighten_hvm.c b/arch/x86/xen/enlighten_hvm.c index 9e87ab010c82b..ec50b7423a4c8 100644 --- a/arch/x86/xen/enlighten_hvm.c +++ b/arch/x86/xen/enlighten_hvm.c @@ -188,6 +188,8 @@ 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()) @@ -207,7 +209,7 @@ 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(); @@ -233,6 +235,13 @@ 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())