From: Eduardo Habkost <ehabkost@redhat.com>
To: Chenyi Qiang <chenyi.qiang@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Richard Henderson <richard.henderson@linaro.org>,
qemu-devel@nongnu.org, Xiaoyao Li <xiaoyao.li@intel.com>
Subject: Re: [PATCH v4] i386: Add ratelimit for bus locks acquired in guest
Date: Tue, 1 Jun 2021 16:10:51 -0400 [thread overview]
Message-ID: <20210601201051.keixbycislhcsgkc@habkost.net> (raw)
In-Reply-To: <20210601181837.dl5tcyqywtoidu57@habkost.net>
On Tue, Jun 01, 2021 at 02:18:37PM -0400, Eduardo Habkost wrote:
> On Mon, May 31, 2021 at 01:14:54PM +0800, Chenyi Qiang wrote:
> >
> >
> > On 5/28/2021 5:19 AM, Eduardo Habkost wrote:
> > > On Fri, May 21, 2021 at 12:38:20PM +0800, Chenyi Qiang wrote:
> > > [...]
> > > > @@ -4222,6 +4247,15 @@ void kvm_arch_pre_run(CPUState *cpu, struct kvm_run *run)
> > > > }
> > > > }
> > > > +static void kvm_rate_limit_on_bus_lock(void)
> > > > +{
> > > > + uint64_t delay_ns = ratelimit_calculate_delay(&bus_lock_ratelimit_ctrl, 1);
> > > > +
> > > > + if (delay_ns) {
> > > > + g_usleep(delay_ns / SCALE_US);
> > > > + }
> > > > +}
> > > > +
> > > > MemTxAttrs kvm_arch_post_run(CPUState *cpu, struct kvm_run *run)
> > > > {
> > > > X86CPU *x86_cpu = X86_CPU(cpu);
> > > > @@ -4237,6 +4271,9 @@ MemTxAttrs kvm_arch_post_run(CPUState *cpu, struct kvm_run *run)
> > > > } else {
> > > > env->eflags &= ~IF_MASK;
> > > > }
> > > > + if (run->flags & KVM_RUN_X86_BUS_LOCK) {
> > >
> > > Does the KVM API guarantee that KVM_RUN_X86_BUS_LOCK will never
> > > be set if KVM_BUS_LOCK_DETECTION_EXIT isn't enabled? (Otherwise
> > > we risk crashing in ratelimit_calculate_delay() above if rate
> > > limiting is disabled).
> > >
> >
> > Yes. KVM_RUN_X86_BUS_LOCK flag is set when bus lock VM exit happens. Bus
> > lock VM exit is disabled by default and can only be enabled through the
> > KVM_BUS_LOCK_DETECTION_EXIT capability.
>
> I'm queueing on x86-next, thanks!
This breaks the build. Is there a linux-headers update patch I've missed?
../target/i386/kvm/kvm.c: In function 'kvm_arch_init':
../target/i386/kvm/kvm.c:2322:42: error: 'KVM_CAP_X86_BUS_LOCK_EXIT' undeclared (first use in this function); did you mean 'KVM_CAP_X86_DISABLE_EXITS'?
ret = kvm_check_extension(s, KVM_CAP_X86_BUS_LOCK_EXIT);
^~~~~~~~~~~~~~~~~~~~~~~~~
KVM_CAP_X86_DISABLE_EXITS
--
Eduardo
next prev parent reply other threads:[~2021-06-01 20:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-21 4:38 [PATCH v4] i386: Add ratelimit for bus locks acquired in guest Chenyi Qiang
2021-05-27 21:19 ` Eduardo Habkost
2021-05-31 5:14 ` Chenyi Qiang
2021-06-01 18:18 ` Eduardo Habkost
2021-06-01 20:10 ` Eduardo Habkost [this message]
2021-06-02 1:26 ` Chenyi Qiang
2021-07-27 8:28 ` Dr. David Alan Gilbert
2021-07-28 5:40 ` Chenyi Qiang
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