From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Gibson Subject: Re: [PATCH 15/19] KVM: PPC: Book3S HV: add get/set accessors for the source configuration Date: Fri, 8 Feb 2019 16:15:43 +1100 Message-ID: <20190208051543.GE2688@umbus.fritz.box> References: <20190107184331.8429-16-clg@kaod.org> <20190204052148.GH1927@umbus.fritz.box> <02ee0470-3c6a-5c5c-a903-44e172ce1ed5@kaod.org> <20190205053233.GG22661@umbus.fritz.box> <20190206012329.GQ22661@umbus.fritz.box> <20190206012447.GR22661@umbus.fritz.box> <1d92005a-c12d-1a55-d01b-98eded13629c@kaod.org> <20190207024855.GZ22661@umbus.fritz.box> <9f03f232-1c47-6e27-6d79-3bcc900fe943@kaod.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="7CZp05NP8/gJM8Cl" Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org To: =?iso-8859-1?Q?C=E9dric?= Le Goater Return-path: Content-Disposition: inline In-Reply-To: <9f03f232-1c47-6e27-6d79-3bcc900fe943@kaod.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppe-linuxppc-embedded-2=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" List-Id: kvm.vger.kernel.org --7CZp05NP8/gJM8Cl Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Feb 07, 2019 at 10:13:48AM +0100, C=E9dric Le Goater wrote: > On 2/7/19 3:48 AM, David Gibson wrote: > > On Wed, Feb 06, 2019 at 08:07:36AM +0100, C=E9dric Le Goater wrote: > >> On 2/6/19 2:24 AM, David Gibson wrote: > >>> On Wed, Feb 06, 2019 at 12:23:29PM +1100, David Gibson wrote: > >>>> On Tue, Feb 05, 2019 at 02:03:11PM +0100, C=E9dric Le Goater wrote: > >>>>> On 2/5/19 6:32 AM, David Gibson wrote: > >>>>>> On Mon, Feb 04, 2019 at 05:07:28PM +0100, C=E9dric Le Goater wrote: > >>>>>>> On 2/4/19 6:21 AM, David Gibson wrote: > >>>>>>>> On Mon, Jan 07, 2019 at 07:43:27PM +0100, C=E9dric Le Goater wro= te: > >>>>>>>>> Theses are use to capure the XIVE EAS table of the KVM device, = the > >>>>>>>>> configuration of the source targets. > >>>>>>>>> > >>>>>>>>> Signed-off-by: C=E9dric Le Goater > >>>>>>>>> --- > >>>>>>>>> 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 */ > >>>>>>>>> =20 > >>>>>>>>> /* Layout of 64-bit XIVE source attribute values */ > >>>>>>>>> #define KVM_XIVE_LEVEL_SENSITIVE (1ULL << 0) > >>>>>>>>> #define KVM_XIVE_LEVEL_ASSERTED (1ULL << 1) > >>>>>>>>> =20 > >>>>>>>>> +/* 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/power= pc/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; > >>>>>>>>> } > >>>>>>>>> =20 > >>>>>>>>> +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 termin= ology > >>>>>>>> of the PAPR hcalls. Which, yes, is basically implemented by set= ting > >>>>>>>> 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 ca= n to > >>>>>>>> the PAPR terminology. > >>>>>>> > >>>>>>> But we don't have an equivalent name in the PAPR specs for the tu= ple=20 > >>>>>>> (prio, server). We could use the generic 'target' name may be ? e= ven=20 > >>>>>>> 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.=20 > >>>>>>> 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= =20 > >>>>> 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. =20 > >> > >> No indeed. I have move them to standard hcalls in the current version. > >> > >>> 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()? > >> > >> Yes. I think we could.=20 > >=20 > > Great! > >=20 > >> The hcalls H_INT_SET_SOURCE_CONFIG and H_INT_SET_QUEUE_CONFIG and=20 > >> the KVM ioctls to set the EQ and the SOURCE configuration have a=20 > >> lot in common. I need to look at how we can plug the KVM ioctl in=20 > >> the hcalls under QEMU. > >> > >> We will have to convert the returned error to respect the PAPR=20 > >> specs or have the ioctls return H_* errors. > >=20 > > I don't think returning H_* values from a kernel call is a good idea. > > Converting errors is kinda ugly, but I still think it's the better > > option. Note that we already have something like this for the HPT > > resizing hcalls. >=20 > ok. > =20 > >> Let's dig that idea. If we choose that path, QEMU will have an=20 > >> up-to-date EAT and so we won't need to synchronize its state anymore= =20 > >> for migration. > >=20 > > I guess so, though I don't see that as essential. > >=20 > >> H_INT_GET_SOURCE_CONFIG can be implemented in QEMU without any KVM=20 > >> ioctl. > >> > >> H_INT_GET_QUEUE_INFO could be implemented in QEMU. I need to check=20 > >> how we return the address of the END ESB in sPAPR. We haven't paid=20 > >> much attention to these pages because they are not used under Linux > >> and today the address is returned by OPAL.=20 > >> > >> H_INT_GET_QUEUE_CONFIG is a little more problematic because we need > >> to query into the XIVE HW the EQ index and toggle bit. OPAL support > >> is required for that. But we could reduce the KVM support to the=20 > >> ioctl querying these EQ information. > >=20 > > Right, and we'd need an ioctl() like that for migration anyway, yes? >=20 > Yes. it is the same need. >=20 > >> H_INT_ESB could be entirely done under QEMU. > >=20 > > This one can actually happen on fairly hot paths, so I think doing > > that in qemu probably isn't a good idea. >=20 > I agree It would nice to have some performance. >=20 > This hcall is used when LSIs are involved, which is not really a common= =20 > configuration. There are no OPAL calls involved. And we are duplicating= =20 > code at the KVM level to retrigger the interrupt when the level is still > asserted. >=20 > I will benchmark the two options before making a choice. Ok. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. 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