From 30978346372e5c43a652cfbd4533c6bd5427c33b Mon Sep 17 00:00:00 2001 From: Zhenzhong Duan Date: Thu, 11 Jul 2019 20:02:09 +0800 Subject: x86: Add "nopv" parameter to disable PV extensions In virtualization environment, PV extensions (drivers, interrupts, timers, etc) are enabled in the majority of use cases which is the best option. However, in some cases (kexec not fully working, benchmarking) we want to disable PV extensions. We have "xen_nopv" for that purpose but only for XEN. For a consistent admin experience a common command line parameter "nopv" set across all PV guest implementations is a better choice. There are guest types which just won't work without PV extensions, like Xen PV, Xen PVH and jailhouse. add a "ignore_nopv" member to struct hypervisor_x86 set to true for those guest types and call the detect functions only if nopv is false or ignore_nopv is true. Suggested-by: Juergen Gross Signed-off-by: Zhenzhong Duan Reviewed-by: Juergen Gross Cc: Thomas Gleixner Cc: Ingo Molnar Cc: Borislav Petkov Cc: Jan Kiszka Cc: Boris Ostrovsky Cc: Stefano Stabellini Signed-off-by: Juergen Gross --- arch/x86/kernel/cpu/hypervisor.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/x86/kernel/cpu') diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c index 87e39ad8d873..7eaad41c68f4 100644 --- a/arch/x86/kernel/cpu/hypervisor.c +++ b/arch/x86/kernel/cpu/hypervisor.c @@ -58,6 +58,14 @@ static const __initconst struct hypervisor_x86 * const hypervisors[] = enum x86_hypervisor_type x86_hyper_type; EXPORT_SYMBOL(x86_hyper_type); +bool __initdata nopv; +static __init int parse_nopv(char *arg) +{ + nopv = true; + return 0; +} +early_param("nopv", parse_nopv); + static inline const struct hypervisor_x86 * __init detect_hypervisor_vendor(void) { @@ -65,6 +73,9 @@ detect_hypervisor_vendor(void) uint32_t pri, max_pri = 0; for (p = hypervisors; p < hypervisors + ARRAY_SIZE(hypervisors); p++) { + if (unlikely(nopv) && !(*p)->ignore_nopv) + continue; + pri = (*p)->detect(); if (pri > max_pri) { max_pri = pri; -- cgit