From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mackerras Subject: Re: [PATCH v2 06/16] KVM: PPC: Book3S HV: XIVE: add controls for the EQ configuration Date: Tue, 26 Feb 2019 16:24:29 +1100 Message-ID: <20190226052429.GC28015@blackberry> References: <20190222112840.25000-1-clg@kaod.org> <20190222112840.25000-7-clg@kaod.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Gibson To: =?iso-8859-1?Q?C=E9dric?= Le Goater Return-path: Content-Disposition: inline In-Reply-To: <20190222112840.25000-7-clg@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 On Fri, Feb 22, 2019 at 12:28:30PM +0100, Cédric Le Goater wrote: > These controls will be used by the H_INT_SET_QUEUE_CONFIG and > H_INT_GET_QUEUE_CONFIG hcalls from QEMU. They will also be used to > restore the configuration of the XIVE EQs in the KVM device and to > capture the internal runtime state of the EQs. Both 'get' and 'set' > rely on an OPAL call to access from the XIVE interrupt controller the > EQ toggle bit and EQ index which are updated by the HW when event > notifications are enqueued in the EQ. > > The value of the guest physical address of the event queue is saved in > the XIVE internal xive_q structure for later use. That is when > migration needs to mark the EQ pages dirty to capture a consistent > memory state of the VM. > > To be noted that H_INT_SET_QUEUE_CONFIG does not require the extra > OPAL call setting the EQ toggle bit and EQ index to configure the EQ, > but restoring the EQ state will. [snip] > +/* Layout of 64-bit eq attribute */ > +#define KVM_XIVE_EQ_PRIORITY_SHIFT 0 > +#define KVM_XIVE_EQ_PRIORITY_MASK 0x7 > +#define KVM_XIVE_EQ_SERVER_SHIFT 3 > +#define KVM_XIVE_EQ_SERVER_MASK 0xfffffff8ULL > + > +/* Layout of 64-bit eq attribute values */ > +struct kvm_ppc_xive_eq { > + __u32 flags; > + __u32 qsize; > + __u64 qpage; > + __u32 qtoggle; > + __u32 qindex; > + __u8 pad[40]; > +}; This is confusing. What's the difference between an "eq attribute" and an "eq attribute value"? Is the first actually a queue index or a queue identifier? Also, the kvm_ppc_xive_eq is not 64 bits, so the comment above it is wrong. Maybe you meant "64-byte"? [snip] > + page = gfn_to_page(kvm, gpa_to_gfn(kvm_eq.qpage)); > + if (is_error_page(page)) { > + pr_warn("Couldn't get guest page for %llx!\n", kvm_eq.qpage); > + return -ENOMEM; > + } > + qaddr = page_to_virt(page) + (kvm_eq.qpage & ~PAGE_MASK); Isn't this assuming that we can map the whole queue with a single gfn_to_page? That would only be true if kvm_eq.qsize <= PAGE_SHIFT. What happens if kvm_eq.qsize > PAGE_SHIFT? Paul. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Mackerras Date: Tue, 26 Feb 2019 05:24:29 +0000 Subject: Re: [PATCH v2 06/16] KVM: PPC: Book3S HV: XIVE: add controls for the EQ configuration Message-Id: <20190226052429.GC28015@blackberry> List-Id: References: <20190222112840.25000-1-clg@kaod.org> <20190222112840.25000-7-clg@kaod.org> In-Reply-To: <20190222112840.25000-7-clg@kaod.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable To: =?iso-8859-1?Q?C=E9dric?= Le Goater Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, David Gibson On Fri, Feb 22, 2019 at 12:28:30PM +0100, C=E9dric Le Goater wrote: > These controls will be used by the H_INT_SET_QUEUE_CONFIG and > H_INT_GET_QUEUE_CONFIG hcalls from QEMU. They will also be used to > restore the configuration of the XIVE EQs in the KVM device and to > capture the internal runtime state of the EQs. Both 'get' and 'set' > rely on an OPAL call to access from the XIVE interrupt controller the > EQ toggle bit and EQ index which are updated by the HW when event > notifications are enqueued in the EQ. >=20 > The value of the guest physical address of the event queue is saved in > the XIVE internal xive_q structure for later use. That is when > migration needs to mark the EQ pages dirty to capture a consistent > memory state of the VM. >=20 > To be noted that H_INT_SET_QUEUE_CONFIG does not require the extra > OPAL call setting the EQ toggle bit and EQ index to configure the EQ, > but restoring the EQ state will. [snip] > +/* Layout of 64-bit eq attribute */ > +#define KVM_XIVE_EQ_PRIORITY_SHIFT 0 > +#define KVM_XIVE_EQ_PRIORITY_MASK 0x7 > +#define KVM_XIVE_EQ_SERVER_SHIFT 3 > +#define KVM_XIVE_EQ_SERVER_MASK 0xfffffff8ULL > + > +/* Layout of 64-bit eq attribute values */ > +struct kvm_ppc_xive_eq { > + __u32 flags; > + __u32 qsize; > + __u64 qpage; > + __u32 qtoggle; > + __u32 qindex; > + __u8 pad[40]; > +}; This is confusing. What's the difference between an "eq attribute" and an "eq attribute value"? Is the first actually a queue index or a queue identifier? Also, the kvm_ppc_xive_eq is not 64 bits, so the comment above it is wrong. Maybe you meant "64-byte"? [snip] > + page =3D gfn_to_page(kvm, gpa_to_gfn(kvm_eq.qpage)); > + if (is_error_page(page)) { > + pr_warn("Couldn't get guest page for %llx!\n", kvm_eq.qpage); > + return -ENOMEM; > + } > + qaddr =3D page_to_virt(page) + (kvm_eq.qpage & ~PAGE_MASK); Isn't this assuming that we can map the whole queue with a single gfn_to_page? That would only be true if kvm_eq.qsize <=3D PAGE_SHIFT. What happens if kvm_eq.qsize > PAGE_SHIFT? Paul.