[PATCH 15/19] KVM: PPC: Book3S HV: add get/set accessors for the source configuration

[David Gibson]

On Wed, Feb 06, 2019 at 12:23:29PM +1100, David Gibson wrote:
> On Tue, Feb 05, 2019 at 02:03:11PM +0100, Cédric Le Goater wrote:
> > On 2/5/19 6:32 AM, David Gibson wrote:
> > > On Mon, Feb 04, 2019 at 05:07:28PM +0100, Cédric Le Goater wrote:
> > >> On 2/4/19 6:21 AM, David Gibson wrote:
> > >>> On Mon, Jan 07, 2019 at 07:43:27PM +0100, Cédric Le Goater wrote:
> > >>>> Theses are use to capure the XIVE EAS table of the KVM device, the
> > >>>> configuration of the source targets.
> > >>>>
> > >>>> Signed-off-by: Cédric Le Goater <clg at kaod.org>
> > >>>> ---
> > >>>>  arch/powerpc/include/uapi/asm/kvm.h   | 11 ++++
> > >>>>  arch/powerpc/kvm/book3s_xive_native.c | 87 +++++++++++++++++++++++++++
> > >>>>  2 files changed, 98 insertions(+)
> > >>>>
> > >>>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
> > >>>> index 1a8740629acf..faf024f39858 100644
> > >>>> --- a/arch/powerpc/include/uapi/asm/kvm.h
> > >>>> +++ b/arch/powerpc/include/uapi/asm/kvm.h
> > >>>> @@ -683,9 +683,20 @@ struct kvm_ppc_cpu_char {
> > >>>>  #define   KVM_DEV_XIVE_SAVE_EQ_PAGES	4
> > >>>>  #define KVM_DEV_XIVE_GRP_SOURCES	2	/* 64-bit source attributes */
> > >>>>  #define KVM_DEV_XIVE_GRP_SYNC		3	/* 64-bit source attributes */
> > >>>> +#define KVM_DEV_XIVE_GRP_EAS		4	/* 64-bit eas attributes */
> > >>>>  
> > >>>>  /* Layout of 64-bit XIVE source attribute values */
> > >>>>  #define KVM_XIVE_LEVEL_SENSITIVE	(1ULL << 0)
> > >>>>  #define KVM_XIVE_LEVEL_ASSERTED		(1ULL << 1)
> > >>>>  
> > >>>> +/* Layout of 64-bit eas attribute values */
> > >>>> +#define KVM_XIVE_EAS_PRIORITY_SHIFT	0
> > >>>> +#define KVM_XIVE_EAS_PRIORITY_MASK	0x7
> > >>>> +#define KVM_XIVE_EAS_SERVER_SHIFT	3
> > >>>> +#define KVM_XIVE_EAS_SERVER_MASK	0xfffffff8ULL
> > >>>> +#define KVM_XIVE_EAS_MASK_SHIFT		32
> > >>>> +#define KVM_XIVE_EAS_MASK_MASK		0x100000000ULL
> > >>>> +#define KVM_XIVE_EAS_EISN_SHIFT		33
> > >>>> +#define KVM_XIVE_EAS_EISN_MASK		0xfffffffe00000000ULL
> > >>>> +
> > >>>>  #endif /* __LINUX_KVM_POWERPC_H */
> > >>>> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
> > >>>> index f2de1bcf3b35..0468b605baa7 100644
> > >>>> --- a/arch/powerpc/kvm/book3s_xive_native.c
> > >>>> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> > >>>> @@ -525,6 +525,88 @@ static int kvmppc_xive_native_sync(struct kvmppc_xive *xive, long irq, u64 addr)
> > >>>>  	return 0;
> > >>>>  }
> > >>>>  
> > >>>> +static int kvmppc_xive_native_set_eas(struct kvmppc_xive *xive, long irq,
> > >>>> +				      u64 addr)
> > >>>
> > >>> I'd prefer to avoid the name "EAS" here.  IIUC these aren't "raw" EAS
> > >>> values, but rather essentially the "source config" in the terminology
> > >>> of the PAPR hcalls.  Which, yes, is basically implemented by setting
> > >>> the EAS, but since it's the PAPR architected state that we need to
> > >>> preserve across migration, I'd prefer to stick as close as we can to
> > >>> the PAPR terminology.
> > >>
> > >> But we don't have an equivalent name in the PAPR specs for the tuple 
> > >> (prio, server). We could use the generic 'target' name may be ? even 
> > >> if this is usually referring to a CPU number.
> > > 
> > > Um.. what?  That's about terminology for one of the fields in this
> > > thing, not about the name for the thing itself.
> > > 
> > >> Or, IVE (Interrupt Vector Entry) ? which makes some sense. 
> > >> This is was the former name in HW. I think we recycle it for KVM.
> > > 
> > > That's a terrible idea, which will make a confusing situation even
> > > more confusing.
> > 
> > Let's use SOURCE_CONFIG and QUEUE_CONFIG. The KVM ioctls are very 
> > similar to the hcalls anyhow.
> 
> Yes, I think that's a good idea.

Actually... AIUI the SET_CONFIG hcalls shouldn't be a fast path.  Can
we simplify things further by removing the hcall implementation from
the kernel entirely, and have qemu implement them by basically just
forwarding them to the appropriate SET_CONFIG ioctl()?

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson
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