From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: kvm-ppc@vger.kernel.org
Subject: Re: [PATCH 16/27] Add desktop PowerPC specific emulation
Date: Sat, 10 Oct 2009 23:14:17 +0000 [thread overview]
Message-ID: <1255216457.2192.16.camel@pasglop> (raw)
In-Reply-To: <1254212303-8737-17-git-send-email-agraf@suse.de>
On Fri, 2009-10-09 at 13:57 -0700, Hollis Blanchard wrote:
> > +#ifdef CONFIG_PPC64
> > +#ifdef DEBUG_EMUL
> > + printk(KERN_INFO "mtDEC: %x\n", vcpu->arch.dec);
> > +#endif
> > + /* POWER4+ triggers a dec interrupt if the value is < 0 */
> > + if (vcpu->arch.dec & 0x80000000) {
> > + del_timer(&vcpu->arch.dec_timer);
> > + kvmppc_core_queue_dec(vcpu);
> > + }
> > + else if (true) {
> > +#else
> > if (vcpu->arch.tcr & TCR_DIE) {
> > +#endif
> > /* The decrementer ticks at the same rate as the timebase, so
> > * that's how we convert the guest DEC value to the number of
> > * host ticks. */
>
> Ifdefs through the middle of control syntax makes my head hurt. :)
Note that your original BookE DEC emulation looks fishy :-)
I may have missed something in your code... but I don't think it
emulates the expected HW behaviour:
Basically, when the BookE DEC hits the 1 -> 0 transition it latches an
event in TSE:DIS always, whether TCR:DIE is set or not. If DIE is not
set, the interrupt is sent. It will then stop counting if auto-reload
isn't enabled.
That means that if TSR:DIS is set from a previous event while TCR:DIE is
clear, then setting TCR:DIE (with MSR:EE enabled of course) will trigger
a DEC interrupt on BookE.
The BookE DEC interrupt is basically a level sensitive thing sourced
from to (TSR:DIS && TCR:DIE), and TSR:DIS remains set until explicitely
cleared.
Cheers,
Ben.
next prev parent reply other threads:[~2009-10-10 23:14 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-29 8:18 [PATCH 16/27] Add desktop PowerPC specific emulation Alexander Graf
2009-10-09 20:57 ` Hollis Blanchard
2009-10-10 23:14 ` Benjamin Herrenschmidt [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-10-21 15:03 [PATCH 00/27] Add KVM support for Book3s_64 (PPC64) hosts v5 Alexander Graf
2009-10-21 15:03 ` [PATCH 01/27] Move dirty logging code to sub-arch Alexander Graf
2009-10-21 15:03 ` [PATCH 02/27] Pass PVR in sregs Alexander Graf
2009-10-21 15:03 ` [PATCH 03/27] Add Book3s definitions Alexander Graf
2009-10-21 15:03 ` [PATCH 04/27] Add Book3s fields to vcpu structs Alexander Graf
2009-10-21 15:03 ` [PATCH 05/27] Add asm/kvm_book3s.h Alexander Graf
2009-10-21 15:03 ` [PATCH 06/27] Add Book3s_64 intercept helpers Alexander Graf
2009-10-21 15:03 ` [PATCH 07/27] Add book3s_64 highmem asm code Alexander Graf
2009-10-21 15:03 ` [PATCH 08/27] Add SLB switching code for entry/exit Alexander Graf
2009-10-21 15:03 ` [PATCH 09/27] Add interrupt handling code Alexander Graf
2009-10-21 15:03 ` [PATCH 10/27] Add book3s.c Alexander Graf
2009-10-21 15:03 ` [PATCH 11/27] Add book3s_64 Host MMU handling Alexander Graf
2009-10-21 15:03 ` [PATCH 12/27] Add book3s_64 guest MMU Alexander Graf
2009-10-21 15:03 ` [PATCH 13/27] Add book3s_32 " Alexander Graf
2009-10-21 15:03 ` [PATCH 14/27] Add book3s_64 specific opcode emulation Alexander Graf
2009-10-21 15:03 ` [PATCH 15/27] Add mfdec emulation Alexander Graf
[not found] ` <1256137413-15256-16-git-send-email-agraf-l3A5Bk7waGM@public.gmane.org>
2009-10-21 15:03 ` [PATCH 16/27] Add desktop PowerPC specific emulation Alexander Graf
2009-10-30 15:47 [PATCH 00/27] Add KVM support for Book3s_64 (PPC64) hosts v6 Alexander Graf
[not found] ` <1256917647-6200-1-git-send-email-agraf-l3A5Bk7waGM@public.gmane.org>
2009-10-30 15:47 ` [PATCH 16/27] Add desktop PowerPC specific emulation Alexander Graf
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