On 05/09/2013 03:51 PM, Bhushan Bharat-R65777 wrote:
-----Original Message-----
From: tiejun.chen [mailto:tiejun.c...@windriver.com]
Sent: Thursday, May 09, 2013 1:18 PM
To: Bhushan Bharat-R65777
Cc: Caraman Mihai Claudiu-B02008; Wood Scott-B07421; linuxppc-
d...@lists.ozlabs.org; ag...@suse.de; kvm-...@vger.kernel.org;
kvm@vger.kernel.org
Subject: Re: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable interrupts
On 05/09/2013 03:33 PM, Bhushan Bharat-R65777 wrote:
-----Original Message-----
From: Linuxppc-dev [mailto:linuxppc-dev-
bounces+bharat.bhushan=freescale....@lists.ozlabs.org] On Behalf Of
bounces+Caraman
Mihai Claudiu-B02008
Sent: Wednesday, May 08, 2013 6:44 PM
To: Wood Scott-B07421; tiejun.chen
Cc: linuxppc-...@lists.ozlabs.org; ag...@suse.de;
kvm-...@vger.kernel.org; kvm@vger.kernel.org
Subject: RE: [RFC][KVM][PATCH 1/1] kvm:ppc:booke-64: soft-disable
interrupts
This only disable soft interrupt for kvmppc_restart_interrupt()
that restarts interrupts if they were meant for the host:
a. SOFT_DISABLE_INTS() only for BOOKE_INTERRUPT_EXTERNAL |
BOOKE_INTERRUPT_DECREMENTER | BOOKE_INTERRUPT_DOORBELL
Those aren't the only exceptions that can end up going to the host.
We could get a TLB miss that results in a heavyweight MMIO exit, etc.
And shouldn't we handle kvmppc_restart_interrupt() like the
original HOST flow?
#define MASKABLE_EXCEPTION(trapnum, intnum, label, hdlr,
ack) \
START_EXCEPTION(label); \
NORMAL_EXCEPTION_PROLOG(trapnum, intnum,
PROLOG_ADDITION_MASKABLE)\
EXCEPTION_COMMON(trapnum, PACA_EXGEN,
*INTS_DISABLE*) \
...
Could you elaborate on what you mean?
I think Tiejun was saying that host has flags and replays only
EE/DEC/DBELL interrupts. There is special macro
masked_interrupt_book3e in those exception handlers that sets paca-
irq_happened.
The list of replied interrupts is limited to asynchronous noncritical
interrupts which can be masked by MSR[EE] (therefore no TLB miss).
Embedded Perfmon interrupt is also asynchronous, Why that is not in the list
of masked interruts.
Are you saying perfmon? If so, its also in that list:
START_EXCEPTION(perfmon);
NORMAL_EXCEPTION_PROLOG(0x260, BOOKE_INTERRUPT_PERFORMANCE_MONITOR,
PROLOG_ADDITION_NONE)
EXCEPTION_COMMON(0x260, PACA_EXGEN, INTS_DISABLE)
Where it is recorded in paca->irq_happned to be replayed later ?
In stead of PROLOG_ADDITION_MASKABLE, actually we have nothing to do with
PROLOG_ADDITION_NONE for perfmon, so perfmon can be executed without lazy state.
Tiejun
Tiejun
-Bharat
Now on KVM book3e we
don't want to put them in the irq_happened lazy state but rather to
execute them directly, so there is no reason for exception handling
symmetry between host and guest.
-Mike
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
