RE: [PATCH v2 3/4] kvm/ppc: Call trace_hardirqs_on before entry

2013-05-09 Thread Bhushan Bharat-R65777 


 -Original Message-
 From: kvm-ow...@vger.kernel.org [mailto:kvm-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 3/4] kvm/ppc: Call trace_hardirqs_on before entry
 
 Currently this is only being done on 64-bit.  Rather than just move it
 out of the 64-bit ifdef, move it to kvm_lazy_ee_enable() so that it is
 consistent with lazy ee state, and so that we don't track more host
 code as interrupts-enabled than necessary.
 
 Rename kvm_lazy_ee_enable() to kvm_fix_ee_before_entry() to reflect
 that this function now has a role on 32-bit as well.
 
 Signed-off-by: Scott Wood scottw...@freescale.com
 ---
  arch/powerpc/include/asm/kvm_ppc.h |   11 ---
  arch/powerpc/kvm/book3s_pr.c   |4 ++--
  arch/powerpc/kvm/booke.c   |4 ++--
  arch/powerpc/kvm/powerpc.c |2 --
  4 files changed, 12 insertions(+), 9 deletions(-)
 
 diff --git a/arch/powerpc/include/asm/kvm_ppc.h
 b/arch/powerpc/include/asm/kvm_ppc.h
 index a5287fe..6885846 100644
 --- a/arch/powerpc/include/asm/kvm_ppc.h
 +++ b/arch/powerpc/include/asm/kvm_ppc.h
 @@ -394,10 +394,15 @@ static inline void kvmppc_mmu_flush_icache(pfn_t pfn)
   }
  }
 
 -/* Please call after prepare_to_enter. This function puts the lazy ee state
 -   back to normal mode, without actually enabling interrupts. */
 -static inline void kvmppc_lazy_ee_enable(void)
 +/*
 + * Please call after prepare_to_enter. This function puts the lazy ee and irq
 + * disabled tracking state back to normal mode, without actually enabling
 + * interrupts.
 + */
 +static inline void kvmppc_fix_ee_before_entry(void)
  {
 + trace_hardirqs_on();
 +
  #ifdef CONFIG_PPC64
   /* Only need to enable IRQs by hard enabling them after this */
   local_paca-irq_happened = 0;
 diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
 index bdc40b8..0b97ce4 100644
 --- a/arch/powerpc/kvm/book3s_pr.c
 +++ b/arch/powerpc/kvm/book3s_pr.c
 @@ -890,7 +890,7 @@ program_interrupt:
   local_irq_enable();
   r = s;
   } else {
 - kvmppc_lazy_ee_enable();
 + kvmppc_fix_ee_before_entry();
   }
   }
 
 @@ -1161,7 +1161,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct
 kvm_vcpu *vcpu)
   if (vcpu-arch.shared-msr  MSR_FP)
   kvmppc_handle_ext(vcpu, BOOK3S_INTERRUPT_FP_UNAVAIL, MSR_FP);
 
 - kvmppc_lazy_ee_enable();
 + kvmppc_fix_ee_before_entry();
 
   ret = __kvmppc_vcpu_run(kvm_run, vcpu);
 
 diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
 index 705fc5c..eb89b83 100644
 --- a/arch/powerpc/kvm/booke.c
 +++ b/arch/powerpc/kvm/booke.c
 @@ -673,7 +673,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct 
 kvm_vcpu
 *vcpu)
   ret = s;
   goto out;
   }
 - kvmppc_lazy_ee_enable();
 + kvmppc_fix_ee_before_entry();

local_irq_disable() is called before kvmppc_prepare_to_enter().
Now we put the irq_happend and soft_enabled back to previous state without 
checking for any interrupt happened in between. If any interrupt happens in 
between, will not that be lost?

-Bharat

 
   kvm_guest_enter();
 
 @@ -1154,7 +1154,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
 kvm_vcpu *vcpu,
   local_irq_enable();
   r = (s  2) | RESUME_HOST | (r  RESUME_FLAG_NV);
   } else {
 - kvmppc_lazy_ee_enable();
 + kvmppc_fix_ee_before_entry();
   }
   }
 
 diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
 index 6316ee3..4e05f8c 100644
 --- a/arch/powerpc/kvm/powerpc.c
 +++ b/arch/powerpc/kvm/powerpc.c
 @@ -117,8 +117,6 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
   kvm_guest_exit();
   continue;
   }
 -
 - trace_hardirqs_on();
  #endif
 
   kvm_guest_enter();
 --
 1.7.10.4
 
 
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Re: [PATCH v2 3/4] kvm/ppc: Call trace_hardirqs_on before entry

2013-05-09 Thread tiejun.chen 

On 05/10/2013 11:34 AM, Bhushan Bharat-R65777 wrote:




-Original Message-
From: kvm-ow...@vger.kernel.org [mailto:kvm-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 3/4] kvm/ppc: Call trace_hardirqs_on before entry

Currently this is only being done on 64-bit.  Rather than just move it
out of the 64-bit ifdef, move it to kvm_lazy_ee_enable() so that it is
consistent with lazy ee state, and so that we don't track more host
code as interrupts-enabled than necessary.

Rename kvm_lazy_ee_enable() to kvm_fix_ee_before_entry() to reflect
that this function now has a role on 32-bit as well.

Signed-off-by: Scott Wood scottw...@freescale.com
---
  arch/powerpc/include/asm/kvm_ppc.h |   11 ---
  arch/powerpc/kvm/book3s_pr.c   |4 ++--
  arch/powerpc/kvm/booke.c   |4 ++--
  arch/powerpc/kvm/powerpc.c |2 --
  4 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/arch/powerpc/include/asm/kvm_ppc.h
b/arch/powerpc/include/asm/kvm_ppc.h
index a5287fe..6885846 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -394,10 +394,15 @@ static inline void kvmppc_mmu_flush_icache(pfn_t pfn)
}
  }

-/* Please call after prepare_to_enter. This function puts the lazy ee state
-   back to normal mode, without actually enabling interrupts. */
-static inline void kvmppc_lazy_ee_enable(void)
+/*
+ * Please call after prepare_to_enter. This function puts the lazy ee and irq
+ * disabled tracking state back to normal mode, without actually enabling
+ * interrupts.
+ */
+static inline void kvmppc_fix_ee_before_entry(void)
  {
+   trace_hardirqs_on();
+
  #ifdef CONFIG_PPC64
/* Only need to enable IRQs by hard enabling them after this */
local_paca-irq_happened = 0;
diff --git a/arch/powerpc/kvm/book3s_pr.c b/arch/powerpc/kvm/book3s_pr.c
index bdc40b8..0b97ce4 100644
--- a/arch/powerpc/kvm/book3s_pr.c
+++ b/arch/powerpc/kvm/book3s_pr.c
@@ -890,7 +890,7 @@ program_interrupt:
local_irq_enable();
r = s;
} else {
-   kvmppc_lazy_ee_enable();
+   kvmppc_fix_ee_before_entry();
}
}

@@ -1161,7 +1161,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct
kvm_vcpu *vcpu)
if (vcpu-arch.shared-msr  MSR_FP)
kvmppc_handle_ext(vcpu, BOOK3S_INTERRUPT_FP_UNAVAIL, MSR_FP);

-   kvmppc_lazy_ee_enable();
+   kvmppc_fix_ee_before_entry();

ret = __kvmppc_vcpu_run(kvm_run, vcpu);

diff --git a/arch/powerpc/kvm/booke.c b/arch/powerpc/kvm/booke.c
index 705fc5c..eb89b83 100644
--- a/arch/powerpc/kvm/booke.c
+++ b/arch/powerpc/kvm/booke.c
@@ -673,7 +673,7 @@ int kvmppc_vcpu_run(struct kvm_run *kvm_run, struct kvm_vcpu
*vcpu)
ret = s;
goto out;
}
-   kvmppc_lazy_ee_enable();
+   kvmppc_fix_ee_before_entry();


local_irq_disable() is called before kvmppc_prepare_to_enter().


In patch 4, we call hard_irq_disable() once enter kvmppc_prepare_to_enter().

Tiejun


Now we put the irq_happend and soft_enabled back to previous state without 
checking for any interrupt happened in between. If any interrupt happens in 
between, will not that be lost?

-Bharat



kvm_guest_enter();

@@ -1154,7 +1154,7 @@ int kvmppc_handle_exit(struct kvm_run *run, struct
kvm_vcpu *vcpu,
local_irq_enable();
r = (s  2) | RESUME_HOST | (r  RESUME_FLAG_NV);
} else {
-   kvmppc_lazy_ee_enable();
+   kvmppc_fix_ee_before_entry();
}
}

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 6316ee3..4e05f8c 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -117,8 +117,6 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
kvm_guest_exit();
continue;
}
-
-   trace_hardirqs_on();
  #endif

kvm_guest_enter();
--
1.7.10.4


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