diff options
| author | Juergen Gross <jgross@suse.com> | 2017-09-06 19:36:25 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2017-10-10 11:50:13 +0200 |
| commit | e6fd28eb3522b31f79a938e24674f77268a120fd (patch) | |
| tree | ae2bca4e5eb15216963d5c168791bce602794468 /arch/x86/xen | |
| parent | 9043442b43b1fddf202591b84702863286700c1a (diff) | |
| download | linux-e6fd28eb3522b31f79a938e24674f77268a120fd.tar.bz2 | |
locking/spinlocks, paravirt, xen: Correct the xen_nopvspin case
With the boot parameter "xen_nopvspin" specified a Xen guest should not
make use of paravirt spinlocks, but behave as if running on bare
metal. This is not true, however, as the qspinlock code will fall back
to a test-and-set scheme when it is detecting a hypervisor.
In order to avoid this disable the virt_spin_lock_key.
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: akataria@vmware.com
Cc: boris.ostrovsky@oracle.com
Cc: chrisw@sous-sol.org
Cc: hpa@zytor.com
Cc: jeremy@goop.org
Cc: rusty@rustcorp.com.au
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20170906173625.18158-3-jgross@suse.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/spinlock.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c index 25a7c4302ce7..e8ab80ad7a6f 100644 --- a/arch/x86/xen/spinlock.c +++ b/arch/x86/xen/spinlock.c @@ -10,6 +10,7 @@ #include <linux/slab.h> #include <asm/paravirt.h> +#include <asm/qspinlock.h> #include <xen/interface/xen.h> #include <xen/events.h> @@ -129,6 +130,7 @@ void __init xen_init_spinlocks(void) if (!xen_pvspin) { printk(KERN_DEBUG "xen: PV spinlocks disabled\n"); + static_branch_disable(&virt_spin_lock_key); return; } printk(KERN_DEBUG "xen: PV spinlocks enabled\n"); |