[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 2/9] xen/arm: Add more registers for saving and restoring vcpu registers
> -----Original Message----- > From: xen-devel-bounces@xxxxxxxxxxxxx [mailto:xen-devel- > bounces@xxxxxxxxxxxxx] On Behalf Of Jaeyong Yoo > Sent: Monday, October 14, 2013 1:39 PM > To: 'Ian Campbell'; 'Tim Deegan' > Cc: 'Stefano Stabellini'; 'Keir Fraser'; 'Jan Beulich'; xen- > devel@xxxxxxxxxxxxx > Subject: Re: [Xen-devel] [PATCH v4 2/9] xen/arm: Add more registers for > saving and restoring vcpu registers > > > -----Original Message----- > > From: xen-devel-bounces@xxxxxxxxxxxxx [mailto:xen-devel- > > bounces@xxxxxxxxxxxxx] On Behalf Of Ian Campbell > > Sent: Friday, October 11, 2013 7:26 PM > > To: Tim Deegan > > Cc: Keir Fraser; Stefano Stabellini; Jan Beulich; Jaeyong Yoo; xen- > > devel@xxxxxxxxxxxxx > > Subject: Re: [Xen-devel] [PATCH v4 2/9] xen/arm: Add more registers > > for saving and restoring vcpu registers > > > > On Fri, 2013-10-11 at 11:22 +0100, Tim Deegan wrote: > > > At 09:43 +0100 on 11 Oct (1381484614), Ian Campbell wrote: > > > > On Fri, 2013-10-11 at 17:30 +0900, Jaeyong Yoo wrote: > > > > > > -----Original Message----- > > > > > > From: xen-devel-bounces@xxxxxxxxxxxxx [mailto:xen-devel- > > > > > > bounces@xxxxxxxxxxxxx] On Behalf Of Ian Campbell > > > > > > Sent: Thursday, October 10, 2013 7:41 PM > > > > > > To: Jaeyong Yoo > > > > > > Cc: Tim Deegan; xen-devel@xxxxxxxxxxxxx > > > > > > Subject: Re: [Xen-devel] [PATCH v4 2/9] xen/arm: Add more > > > > > > registers for saving and restoring vcpu registers > > > > > > > > > > > > On Fri, 2013-10-04 at 13:43 +0900, Jaeyong Yoo wrote: > > > > > > > diff --git a/xen/include/public/arch-arm.h > > > > > > > b/xen/include/public/arch-arm.h index 5d359af..bf6dc9a > > > > > > > 100644 > > > > > > > --- a/xen/include/public/arch-arm.h > > > > > > > +++ b/xen/include/public/arch-arm.h > > > > > > > @@ -253,6 +253,41 @@ struct vcpu_guest_context { > > > > > > > > > > > > > > uint32_t sctlr, ttbcr; > > > > > > > uint64_t ttbr0, ttbr1; > > > > > > > + uint32_t ifar, dfar; > > > > > > > + uint32_t ifsr, dfsr; > > > > > > > + uint32_t dacr; > > > > > > > + uint64_t par; > > > > > > > + > > > > > > > +#ifdef CONFIG_ARM_32 > > > > > > > > > > > > I'm afraid a per arch ifdef isn't allowed in the > > > > > > include/public > > tree. > > > > > > The interface should be identical for both 32 and 64 bit > > > > > > callers. Also think of 32-on-64 guests etc. > > > > > > > > > > > > Also, this struct is guest facing (via VCPUOP_initialise) but > > > > > > many/all of these new registers are not things which a guest > > > > > > needs to specify via a hypercall. IOW I think many of them > > > > > > should be part of some toolstack private save/restore interface. > > > > > > > > > > I see, the guest can specify something like sctlr, and > > > > > ttbr/ttbcr, and the others should be hidden inside hvm > save/restore. > > > > > > > > Right, the important thing is that all that additional state is > > > > only visible to the toolstack and the hypervisor, not to guests. > > > > > > > > Actually the guest shouldn't really see this interface anyway, > > > > that's really a hold over from x86. On ARM only the toolstack > > > > really needs to use this struct. > > > > > > > > I wonder if we can drop struct vcpu_guest_context from the guest > > > > facing ABI on ARM. I see that we already don't expose > > > > VCPUOP_initialise and the only other user is > > XEN_DOMCTL_(sg)etvcpucontext. > > > > > > Does the guest need to have those on ARM? How are you arranging SMP > > > guest AP bringup? If it's using SCI then maybe that hypercall > > > interface can be dropped. > > > > SMP bring up is done via PSCI, which is the firmware "hypercall" > > interface, defined by ARM for bringing up physucal CPUs which we > > implement within Xen for the guests' benefit. > > So, could I remove XEN_DOMCTL_(sg)etvcpucontext and use HVM save/restore > for migrating vcpu registers? > > And, if I could, arch_get_info_guest becomes dangling function and would > it be better to remove this function too? or better to keep it for > symmetry? Are these questions missed? > > Jaeyong > > > > > Ian > > > > > > _______________________________________________ > > Xen-devel mailing list > > Xen-devel@xxxxxxxxxxxxx > > http://lists.xen.org/xen-devel > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@xxxxxxxxxxxxx > http://lists.xen.org/xen-devel _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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