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authorZhenzhong Duan <zhenzhong.duan@oracle.com>2019-10-23 14:16:22 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2020-07-08 23:21:57 +0300
commit05eee619ed61c8cd89633954d38c4e5653086845 (patch)
tree2e535cff34fd3d57031fcdcb30882ec65266ae6c /kernel
parent5aefd786fba7336c1ecc608e2a126e4f45b180d7 (diff)
downloadlinux-05eee619ed61c8cd89633954d38c4e5653086845.tar.xz
x86/kvm: Add "nopvspin" parameter to disable PV spinlocks
There are cases where a guest tries to switch spinlocks to bare metal behavior (e.g. by setting "xen_nopvspin" on XEN platform and "hv_nopvspin" on HYPER_V). That feature is missed on KVM, add a new parameter "nopvspin" to disable PV spinlocks for KVM guest. The new 'nopvspin' parameter will also replace Xen and Hyper-V specific parameters in future patches. Define variable nopvsin as global because it will be used in future patches as above. Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krcmar <rkrcmar@redhat.com> Cc: Sean Christopherson <sean.j.christopherson@intel.com> Cc: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: Wanpeng Li <wanpengli@tencent.com> Cc: Jim Mattson <jmattson@google.com> Cc: Joerg Roedel <joro@8bytes.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will@kernel.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/locking/qspinlock.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c
index b9515fcc9b29..cbff6ba53d56 100644
--- a/kernel/locking/qspinlock.c
+++ b/kernel/locking/qspinlock.c
@@ -581,4 +581,11 @@ EXPORT_SYMBOL(queued_spin_lock_slowpath);
#include "qspinlock_paravirt.h"
#include "qspinlock.c"
+bool nopvspin __initdata;
+static __init int parse_nopvspin(char *arg)
+{
+ nopvspin = true;
+ return 0;
+}
+early_param("nopvspin", parse_nopvspin);
#endif