On 07/12/2013 12:36 AM, Scott Wood wrote:
On 07/11/2013 11:30:41 AM, Alexander Graf wrote:
On 11.07.2013, at 18:18, Scott Wood wrote:
> On 07/11/2013 08:07:30 AM, Alexander Graf wrote:
>> get_paca() warns when we're preemptible. We're only not preemptible when
either preempt is disabled or irqs are disabled. Irqs are disabled, but
arch_irqs_disabled() doesn't know, because it only checks for soft disabled IRQs.
>> So we can fix this either by setting IRQs as soft disabled as well
>
> If we set IRQs as soft-disabled prior to calling hard_irq_disable(), then
hard_irq_disable() will fail to call trace_hardirqs_off().
Right...
Plus we'd have the same problem trying to set soft_enabled to 0.
>> Any preferences?
>
> Use arch_local_save_flags() in hard_irq_disable() instead of reading
soft_enabled with C code.
That only operates on the soft_enabled bit. We also need to access irq_happened.
OK, so we'll need more inline asm.
If so, why not to remove directly hard_irq_disable() inside kvmppc_handle_exit()
by reverting that commit, "kvm/ppc/booke64: Fix lazy ee handling in
kvmppc_handle_exit()"?
Then we can use SOFT_DISABLE_INTS() explicitly before call kvmppc_handle_exit()
like this:
KVM: PPC: Book3E HV: call SOFT_DISABLE_INTS to sync the software state
We enter with interrupts disabled in hardware, but we need to
call SOFT_DISABLE_INTS anyway to ensure that the software state
is kept in sync.
Signed-off-by: Tiejun Chen <tiejun.chen@xxxxxxxxxxxxx>
diff --git a/arch/powerpc/kvm/bookehv_interrupts.S
b/arch/powerpc/kvm/bookehv_interrupts.S
index e8ed7d6..b521d21 100644
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S
@@ -33,6 +33,8 @@
#ifdef CONFIG_64BIT
#include <asm/exception-64e.h>
+#include <asm/hw_irq.h>
+#include <asm/irqflags.h>
#else
#include "../kernel/head_booke.h" /* for THREAD_NORMSAVE() */
#endif
@@ -469,6 +471,14 @@ _GLOBAL(kvmppc_resume_host)
PPC_LL r3, HOST_RUN(r1)
mr r5, r14 /* intno */
mr r14, r4 /* Save vcpu pointer. */
+#ifdef CONFIG_64BIT
+ /*
+ * We enter with interrupts disabled in hardware, but
+ * we need to call SOFT_DISABLE_INTS anyway to ensure
+ * that the software state is kept in sync.
+ */
+ SOFT_DISABLE_INTS(r7,r8)
+#endif
bl kvmppc_handle_exit
/* Restore vcpu pointer and the nonvolatiles we used. */
Tiejun
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