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x86/kvm: Add "nopvspin" parameter to disable PV spinlocks

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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>
This commit is contained in:
Zhenzhong Duan
2019-10-23 19:16:22 +08:00
committed by Paolo Bonzini
parent 5aefd786fb
commit 05eee619ed
4 changed files with 47 additions and 9 deletions
Download Patch File Download Diff File Expand all files Collapse all files

7
kernel/locking/qspinlock.c
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@@ -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