Messages in this thread | | | From | gengdongjiu <> | Subject | Re: [PATCH v9 5/7] arm64: kvm: Introduce KVM_ARM_SET_SERROR_ESR ioctl | Date | Wed, 24 Jan 2018 20:06:15 +0000 |
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Hi James, Thanks a lot for your review and comments.
> > Hi Dongjiu Geng, > > On 06/01/18 16:02, Dongjiu Geng wrote: > > The ARM64 RAS SError Interrupt(SEI) syndrome value is specific to the > > guest and user space needs a way to tell KVM this value. So we add a > > new ioctl. Before user space specifies the Exception Syndrome Register > > ESR(ESR), it firstly checks that whether KVM has the capability to set > > the guest ESR, If has, will set it. Otherwise, nothing to do. > > > > For this ESR specifying, Only support for AArch64, not support AArch32. > > After this patch user-space can trigger an SError in the guest. If it wants to migrate the guest, how does the pending SError get migrated? > > I think we need to fix migration first. Andrew Jones suggested using > KVM_GET/SET_VCPU_EVENTS: > https://www.spinics.net/lists/arm-kernel/msg616846.html > > Given KVM uses kvm_inject_vabt() on v8.0 hardware too, we should cover systems without the v8.2 RAS Extensions with the same API. I > think this means a bit to read/write whether SError is pending, and another to indicate the ESR should be set/read. > CPUs without the v8.2 RAS Extensions can reject pending-SError that had an ESR.
For the CPUs without the v8.2 RAS Extensions, its ESR is always 0, we only can inject a SError with ESR 0 to guest, cannot set its ESR. About how about to use the KVM_GET/SET_VCPU_EVENTS, I will check the code, and consider your suggestion at the same time. The IOCTL KVM_GET/SET_VCPU_EVENTS has been used by X86.
> > user-space can then use the 'for migration' calls to make a 'new' SError pending. > > Now that the cpufeature bits are queued, I think this can be split up into two separate series for v4.16-rc1, one to tackle NOTIFY_SEI and > the associated plumbing. The second for the KVM 'make SError pending' API.
Ok, thanks for your suggestion, will split it.
> > > > diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c index > > 5c7f657..738ae90 100644 > > --- a/arch/arm64/kvm/guest.c > > +++ b/arch/arm64/kvm/guest.c > > @@ -277,6 +277,11 @@ int kvm_arch_vcpu_ioctl_set_sregs(struct kvm_vcpu *vcpu, > > return -EINVAL; > > } > > > > +int kvm_arm_set_sei_esr(struct kvm_vcpu *vcpu, u32 *syndrome) { > > + return -EINVAL; > > +} > > Does nothing in the patch that adds the support? This is a bit odd. > (oh, its hiding in patch 6...)
To make this patch simple and small, I add it in patch 6.
> > > Thanks, > > James
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