From: "Alex Bennée" <alex.bennee@linaro.org>
To: Claudio Fontana <cfontana@suse.de>
Cc: "Peter Maydell" <peter.maydell@linaro.org>,
"Claudio Fontana" <cfontana@centriq4.arch.suse.de>,
"Richard Henderson" <richard.henderson@linaro.org>,
qemu-devel@nongnu.org, "Roman Bolshakov" <r.bolshakov@yadro.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Philippe Mathieu-Daudé" <philmd@redhat.com>,
"Eduardo Habkost" <ehabkost@redhat.com>
Subject: Re: [RFC v1 34/38] target/arm: cpu: only initialize TCG gt timers under CONFIG_TCG
Date: Tue, 23 Feb 2021 11:01:33 +0000 [thread overview]
Message-ID: <87wnuz3v0u.fsf@linaro.org> (raw)
In-Reply-To: <03502e51-99f5-239d-42a6-e57892faa297@suse.de>
Claudio Fontana <cfontana@suse.de> writes:
> On 2/22/21 4:34 PM, Alex Bennée wrote:
>>
>> Claudio Fontana <cfontana@suse.de> writes:
>>
>>> From: Claudio Fontana <cfontana@centriq4.arch.suse.de>
>>>
>>> KVM has its own cpu->kvm_vtime.
>>>
>>> Adjust cpu vmstate by putting unused fields instead of the
>>> VMSTATE_TIMER_PTR when TCG is not available.
>>>
>>> Signed-off-by: Claudio Fontana <cfontana@suse.de>
>>> ---
>>> target/arm/cpu.c | 4 +++-
>>> target/arm/machine.c | 5 +++++
>>> 2 files changed, 8 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/target/arm/cpu.c b/target/arm/cpu.c
>>> index 1d81a1e7ac..b929109054 100644
>>> --- a/target/arm/cpu.c
>>> +++ b/target/arm/cpu.c
>>> @@ -1322,6 +1322,7 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
>>> }
>>> }
>>>
>>> +#ifdef CONFIG_TCG
>>> {
>>> uint64_t scale;
>>>
>>> @@ -1347,7 +1348,8 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
>>> cpu->gt_timer[GTIMER_HYPVIRT] = timer_new(QEMU_CLOCK_VIRTUAL, scale,
>>> arm_gt_hvtimer_cb, cpu);
>>> }
>>> -#endif
>>> +#endif /* CONFIG_TCG */
>>> +#endif /* !CONFIG_USER_ONLY */
>>>
>>> cpu_exec_realizefn(cs, &local_err);
>>> if (local_err != NULL) {
>>> diff --git a/target/arm/machine.c b/target/arm/machine.c
>>> index 666ef329ef..13d7c6d930 100644
>>> --- a/target/arm/machine.c
>>> +++ b/target/arm/machine.c
>>> @@ -822,8 +822,13 @@ const VMStateDescription vmstate_arm_cpu = {
>>> VMSTATE_UINT32(env.exception.syndrome, ARMCPU),
>>> VMSTATE_UINT32(env.exception.fsr, ARMCPU),
>>> VMSTATE_UINT64(env.exception.vaddress, ARMCPU),
>>> +#ifdef CONFIG_TCG
>>> VMSTATE_TIMER_PTR(gt_timer[GTIMER_PHYS], ARMCPU),
>>> VMSTATE_TIMER_PTR(gt_timer[GTIMER_VIRT], ARMCPU),
>>> +#else
>>> + VMSTATE_UNUSED(sizeof(QEMUTimer *)),
>>> + VMSTATE_UNUSED(sizeof(QEMUTimer *)),
>>> +#endif /* CONFIG_TCG */
>>
>> I'm not sure this is correct - VMSTATE_TIMER_PTR chases the links to
>> just expose expired time but QEMUTimer has more in it than that. Paolo
>
>
> I am not sure I follow can you state more precisely where the issue could be?
>
> it's not a VMSTATE_TIMER, it's a VMSTATE_TIMER_PTR,
> it ends up in VMSTATE_POINTER where a single pointer is assigned;
Does it? I thought it ended up with the .expire_time (int64_t) which
will be bigger than sizeof(QemuTimer *) on a 32 bit system.
>
> so if we don't use gt_timer at all (as is the case with !CONFIG_TCG), we just
> need to ensure that an unused number is there to assign, migrating from old to new version?
>
>
>> suggested a straight VMSTATE_UNUSED(8) on IRC but I wonder if it would
>> be better to have a VMSTATE_UNUSED_TIMER?
>>
>> I don't think there is an impact for Xen because I'm fairly certain
>> migration isn't a thing we do - but I'll double check.
>>
>
> Thanks Alex, that would be helpful,
> if Xen uses gt_timer in any way I would not want to unwillingly break
> it.
Not for ARM no, currently there is no ARM specific machine emulated by
QEMU for Xen. All ARM guests are PV guests.
>
> Thanks,
>
> Claudio
--
Alex Bennée
next prev parent reply other threads:[~2021-02-23 11:05 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210221092449.7545-1-cfontana@suse.de>
[not found] ` <20210221092449.7545-33-cfontana@suse.de>
2021-02-21 9:53 ` [RFC v1 32/38] target/arm: cpu: do not initialize TCG PMU for KVM Philippe Mathieu-Daudé
2021-02-21 13:59 ` Claudio Fontana
2021-02-22 6:11 ` Richard Henderson
[not found] ` <20210221092449.7545-35-cfontana@suse.de>
2021-02-21 9:55 ` [RFC v1 34/38] target/arm: cpu: only initialize TCG gt timers under CONFIG_TCG Philippe Mathieu-Daudé
2021-02-21 13:59 ` Claudio Fontana
2021-02-22 8:35 ` Claudio Fontana
2021-03-01 18:19 ` Olaf Hering
[not found] ` <87v9ak5cz0.fsf@linaro.org>
2021-02-23 9:12 ` Claudio Fontana
2021-02-23 11:01 ` Alex Bennée [this message]
2021-02-23 11:36 ` Claudio Fontana
2021-02-23 12:38 ` Claudio Fontana
2021-02-23 14:47 ` Paolo Bonzini
2021-02-22 5:35 ` [RFC v1 00/38] arm cleanup experiment for kvm-only build Richard Henderson
2021-02-22 8:43 ` Claudio Fontana
2021-02-22 11:56 ` Philippe Mathieu-Daudé
2021-02-22 16:08 ` Richard Henderson
2021-02-22 16:57 ` Alex Bennée
2021-02-23 9:17 ` Claudio Fontana
[not found] ` <20210221092449.7545-21-cfontana@suse.de>
2021-02-22 5:48 ` [RFC v1 20/38] target/arm: move arm_hcr_el2_eff to common_cpu Richard Henderson
[not found] ` <20210221092449.7545-24-cfontana@suse.de>
2021-02-22 5:52 ` [RFC v1 23/38] target/arm: move arm_mmu_idx_el to common-cpu Richard Henderson
[not found] ` <20210221092449.7545-25-cfontana@suse.de>
2021-02-22 6:02 ` [RFC v1 24/38] target/arm: move aa64_va_parameter_tbi,tbid,tcma and arm_rebuild_hflags Richard Henderson
2021-02-23 10:07 ` Claudio Fontana
2021-02-23 16:30 ` Richard Henderson
[not found] ` <20210221092449.7545-26-cfontana@suse.de>
2021-02-22 6:04 ` [RFC v1 25/38] target/arm: move fp_exception_el outside of tcg helpers Richard Henderson
[not found] ` <20210221092449.7545-27-cfontana@suse.de>
2021-02-22 6:05 ` [RFC v1 26/38] target/arm: move sve_exception_el to cpu Richard Henderson
[not found] ` <20210221092449.7545-28-cfontana@suse.de>
2021-02-22 6:06 ` [RFC v1 27/38] target/arm: move sve_zcr_len_for_el to common_cpu Richard Henderson
2021-02-25 17:28 ` Claudio Fontana
2021-02-25 20:13 ` Claudio Fontana
2021-02-26 4:01 ` Richard Henderson
[not found] ` <20210221092449.7545-29-cfontana@suse.de>
2021-02-22 6:09 ` [RFC v1 28/38] target/arm: make arm_pmu_timer_cb TCG-only, starting tcg-stub Richard Henderson
[not found] ` <20210221092449.7545-2-cfontana@suse.de>
2021-02-22 6:14 ` [RFC v1 01/38] target/arm: move translate modules to tcg/ Richard Henderson
[not found] ` <20210221092449.7545-4-cfontana@suse.de>
2021-02-22 6:16 ` [RFC v1 03/38] arm: tcg: only build under CONFIG_TCG Richard Henderson
[not found] ` <20210221092449.7545-6-cfontana@suse.de>
2021-02-22 6:21 ` [RFC v1 05/38] target/arm: wrap arm_cpu_exec_interrupt in CONFIG_TCG Richard Henderson
2021-02-22 8:31 ` Claudio Fontana
2021-02-22 15:54 ` Richard Henderson
2021-02-23 8:46 ` Claudio Fontana
[not found] ` <20210221092449.7545-9-cfontana@suse.de>
2021-02-22 6:29 ` [RFC v1 08/38] target/arm/tcg: split softmmu parts of v8_cp_reginfo and el2_cp_reginfo Richard Henderson
[not found] ` <20210221092449.7545-3-cfontana@suse.de>
2021-02-22 6:16 ` [RFC v1 02/38] target/arm: move helpers to tcg/ Richard Henderson
2021-02-22 17:20 ` Philippe Mathieu-Daudé
[not found] ` <20210221092449.7545-5-cfontana@suse.de>
[not found] ` <87eeh857xf.fsf@linaro.org>
2021-02-23 8:44 ` [RFC v1 04/38] target/arm: move psci.c into tcg/softmmu/ Claudio Fontana
[not found] ` <20210221092449.7545-7-cfontana@suse.de>
[not found] ` <87blcc57rj.fsf@linaro.org>
2021-02-23 8:55 ` [RFC v1 06/38] target/arm: split off cpu-softmmu.c Claudio Fontana
2021-02-23 9:16 ` Philippe Mathieu-Daudé
2021-02-23 9:35 ` Claudio Fontana
2021-02-23 18:18 ` softmmu vs sysemu [Was: Re: [RFC v1 06/38] target/arm: split off cpu-softmmu.c] Claudio Fontana
2021-02-23 18:51 ` Richard Henderson
2021-02-23 23:43 ` Philippe Mathieu-Daudé
2021-02-24 0:06 ` Richard Henderson
2021-02-24 9:20 ` Paolo Bonzini
2021-02-24 9:30 ` Claudio Fontana
2021-02-24 10:00 ` Paolo Bonzini
[not found] ` <875z2k53mn.fsf@linaro.org>
2021-02-23 9:18 ` [RFC v1 00/38] arm cleanup experiment for kvm-only build Philippe Mathieu-Daudé
2021-03-01 11:52 ` Claudio Fontana
2021-03-01 16:23 ` Alex Bennée
2021-03-03 17:57 ` Claudio Fontana
2021-03-03 18:09 ` Peter Maydell
2021-03-03 18:17 ` Claudio Fontana
2021-03-03 18:20 ` Claudio Fontana
2021-03-03 18:30 ` Philippe Mathieu-Daudé
2021-03-03 18:39 ` Richard Henderson
2021-03-03 18:45 ` Claudio Fontana
2021-03-03 18:54 ` Richard Henderson
2021-03-04 16:39 ` Philippe Mathieu-Daudé
2021-03-04 17:19 ` Claudio Fontana
2021-03-04 17:47 ` Philippe Mathieu-Daudé
2021-03-04 19:24 ` Peter Maydell
2021-03-05 9:04 ` Claudio Fontana
2021-03-03 18:34 ` Philippe Mathieu-Daudé
2021-03-03 18:38 ` Claudio Fontana
2021-02-23 9:18 ` Claudio Fontana
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