-Original Message-
From: kvm-ppc-ow...@vger.kernel.org [mailto:kvm-ppc-ow...@vger.kernel.org] On
Behalf Of Scott Wood
Sent: Friday, May 10, 2013 8:40 AM
To: Alexander Graf; Benjamin Herrenschmidt
Cc: kvm-ppc@vger.kernel.org; k...@vger.kernel.org;
linuxppc-...@lists.ozlabs.org;
Wood Scott-B07421
Subject: [PATCH v2 4/4] kvm/ppc: IRQ disabling cleanup
Simplify the handling of lazy EE by going directly from fully-enabled
to hard-disabled. This replaces the lazy_irq_pending() check
(including its misplaced kvm_guest_exit() call).
As suggested by Tiejun Chen, move the interrupt disabling into
kvmppc_prepare_to_enter() rather than have each caller do it. Also
move the IRQ enabling on heavyweight exit into
kvmppc_prepare_to_enter().
Don't move kvmppc_fix_ee_before_entry() into kvmppc_prepare_to_enter(),
so that the caller can avoid marking interrupts enabled earlier than
necessary (e.g. book3s_pr waits until after FP save/restore is done).
Signed-off-by: Scott Wood scottw...@freescale.com
---
arch/powerpc/include/asm/kvm_ppc.h |6 ++
arch/powerpc/kvm/book3s_pr.c | 12 +++-
arch/powerpc/kvm/booke.c |9 ++---
arch/powerpc/kvm/powerpc.c | 21 -
4 files changed, 19 insertions(+), 29 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_ppc.h
b/arch/powerpc/include/asm/kvm_ppc.h
index 6885846..e4474f8 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -404,6 +404,12 @@ static inline void kvmppc_fix_ee_before_entry(void)
trace_hardirqs_on();
#ifdef CONFIG_PPC64
+ /*
+ * To avoid races, the caller must have gone directly from having
+ * interrupts fully-enabled to hard-disabled.
+ */
+ WARN_ON(local_paca-irq_happened != PACA_IRQ_HARD_DIS);
+
/* Only need to enable IRQs by hard enabling them after this */
local_paca-irq_happened = 0;
local_paca-soft_enabled = 1;
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index 0b97ce4..e61e39e 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -884,14 +884,11 @@ program_interrupt:
* and if we really did time things so badly, then we just exit
* again due to a host external interrupt.
*/
- local_irq_disable();
s = kvmppc_prepare_to_enter(vcpu);
- if (s = 0) {
- local_irq_enable();
+ if (s = 0)
r = s;
- } else {
+ else
kvmppc_fix_ee_before_entry();
- }
}
trace_kvm_book3s_reenter(r, vcpu);
@@ -1121,12 +1118,9 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct
kvm_vcpu *vcpu)
* really did time things so badly, then we just exit again due to
* a host external interrupt.
*/
- local_irq_disable();
ret = kvmppc_prepare_to_enter(vcpu);
- if (ret = 0) {
- local_irq_enable();
+ if (ret = 0)
goto out;
- }
/* Save FPU state in stack */
if (current-thread.regs-msr MSR_FP)
diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index eb89b83..f7c0111 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -666,10 +666,8 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct
kvm_vcpu *vcpu)
return -EINVAL;
}
- local_irq_disable();
s = kvmppc_prepare_to_enter(vcpu);
if (s = 0) {
- local_irq_enable();
ret = s;
goto out;
}
@@ -1148,14 +1146,11 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
kvm_vcpu *vcpu,
* aren't already exiting to userspace for some other reason.
*/
if (!(r RESUME_HOST)) {
- local_irq_disable();
Ok, Now we do not soft disable before kvmppc_prapare_to_enter().
s = kvmppc_prepare_to_enter(vcpu);
- if (s = 0) {
- local_irq_enable();
+ if (s = 0)
r = (s 2) | RESUME_HOST | (r RESUME_FLAG_NV);
- } else {
+ else
kvmppc_fix_ee_before_entry();
- }
}
return r;
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 4e05f8c..f8659aa 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -64,12 +64,14 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
{
int r = 1;
- WARN_ON_ONCE(!irqs_disabled());
+ WARN_ON(irqs_disabled());
+ hard_irq_disable();
Here we hard disable in kvmppc_prepare_to_enter(), so my comment in other patch
about interrupt loss is no more valid.
So here
MSR.EE = 0
local_paca-soft_enabled = 0
local_paca-irq_happened |= PACA_IRQ_HARD_DIS;
+
while (true)
