From: David Gibson <david@gibson.dropbear.id.au> To: "Cédric Le Goater" <clg@kaod.org> Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras <paulus@samba.org>, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2 03/16] KVM: PPC: Book3S HV: XIVE: introduce a new capability KVM_CAP_PPC_IRQ_XIVE Date: Wed, 13 Mar 2019 15:05:42 +1100 [thread overview] Message-ID: <20190313040542.GL9881@umbus.fritz.box> (raw) In-Reply-To: <2f029721-0b20-2706-6627-0bac36afd03e@kaod.org> [-- Attachment #1: Type: text/plain, Size: 2164 bytes --] On Tue, Mar 12, 2019 at 03:03:25PM +0100, Cédric Le Goater wrote: > On 2/25/19 1:35 AM, David Gibson wrote: > > On Fri, Feb 22, 2019 at 12:28:27PM +0100, Cédric Le Goater wrote: [snip] > >> +int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev, > >> + struct kvm_vcpu *vcpu, u32 cpu) > >> +{ > >> + struct kvmppc_xive *xive = dev->private; > >> + struct kvmppc_xive_vcpu *xc; > >> + int rc; > >> + > >> + pr_devel("native_connect_vcpu(cpu=%d)\n", cpu); > >> + > >> + if (dev->ops != &kvm_xive_native_ops) { > >> + pr_devel("Wrong ops !\n"); > >> + return -EPERM; > >> + } > >> + if (xive->kvm != vcpu->kvm) > >> + return -EPERM; > >> + if (vcpu->arch.irq_type != KVMPPC_IRQ_DEFAULT) > >> + return -EBUSY; > >> + if (kvmppc_xive_find_server(vcpu->kvm, cpu)) { > > > > You haven't taken the kvm->lock yet, so couldn't a race mean a > > duplicate server gets inserted after you make this check? > > > >> + pr_devel("Duplicate !\n"); > >> + return -EEXIST; > >> + } > >> + if (cpu >= KVM_MAX_VCPUS) { > >> + pr_devel("Out of bounds !\n"); > >> + return -EINVAL; > >> + } > >> + xc = kzalloc(sizeof(*xc), GFP_KERNEL); > >> + if (!xc) > >> + return -ENOMEM; > >> + > >> + mutex_lock(&vcpu->kvm->lock); > >> + vcpu->arch.xive_vcpu = xc; > > > > Similarly you don't verify this is NULL after taking the lock, so > > couldn't another thread race and make a connect which gets clobbered > > here? > > Yes. this is not very safe ... We need to clean up all the KVM device > methods doing the connection of the presenter to the vCPU AFAICT. > I will fix the XIVE native one for now. > > And also, this CPU parameter is useless. There is no reason to connect > a vCPU from another vCPU. Hmm.. I thought the point of the 'cpu' parameter (not a great name) is that it lets userspace chose the guest visible irq server ID. I think that's preferable to tying it to an existing cpu id, if possible. -- 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 [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --]
WARNING: multiple messages have this Message-ID (diff)
From: David Gibson <david@gibson.dropbear.id.au> To: "Cédric Le Goater" <clg@kaod.org> Cc: kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, Paul Mackerras <paulus@samba.org>, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2 03/16] KVM: PPC: Book3S HV: XIVE: introduce a new capability KVM_CAP_PPC_IRQ_XIVE Date: Wed, 13 Mar 2019 04:05:42 +0000 [thread overview] Message-ID: <20190313040542.GL9881@umbus.fritz.box> (raw) In-Reply-To: <2f029721-0b20-2706-6627-0bac36afd03e@kaod.org> [-- Attachment #1: Type: text/plain, Size: 2164 bytes --] On Tue, Mar 12, 2019 at 03:03:25PM +0100, Cédric Le Goater wrote: > On 2/25/19 1:35 AM, David Gibson wrote: > > On Fri, Feb 22, 2019 at 12:28:27PM +0100, Cédric Le Goater wrote: [snip] > >> +int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev, > >> + struct kvm_vcpu *vcpu, u32 cpu) > >> +{ > >> + struct kvmppc_xive *xive = dev->private; > >> + struct kvmppc_xive_vcpu *xc; > >> + int rc; > >> + > >> + pr_devel("native_connect_vcpu(cpu=%d)\n", cpu); > >> + > >> + if (dev->ops != &kvm_xive_native_ops) { > >> + pr_devel("Wrong ops !\n"); > >> + return -EPERM; > >> + } > >> + if (xive->kvm != vcpu->kvm) > >> + return -EPERM; > >> + if (vcpu->arch.irq_type != KVMPPC_IRQ_DEFAULT) > >> + return -EBUSY; > >> + if (kvmppc_xive_find_server(vcpu->kvm, cpu)) { > > > > You haven't taken the kvm->lock yet, so couldn't a race mean a > > duplicate server gets inserted after you make this check? > > > >> + pr_devel("Duplicate !\n"); > >> + return -EEXIST; > >> + } > >> + if (cpu >= KVM_MAX_VCPUS) { > >> + pr_devel("Out of bounds !\n"); > >> + return -EINVAL; > >> + } > >> + xc = kzalloc(sizeof(*xc), GFP_KERNEL); > >> + if (!xc) > >> + return -ENOMEM; > >> + > >> + mutex_lock(&vcpu->kvm->lock); > >> + vcpu->arch.xive_vcpu = xc; > > > > Similarly you don't verify this is NULL after taking the lock, so > > couldn't another thread race and make a connect which gets clobbered > > here? > > Yes. this is not very safe ... We need to clean up all the KVM device > methods doing the connection of the presenter to the vCPU AFAICT. > I will fix the XIVE native one for now. > > And also, this CPU parameter is useless. There is no reason to connect > a vCPU from another vCPU. Hmm.. I thought the point of the 'cpu' parameter (not a great name) is that it lets userspace chose the guest visible irq server ID. I think that's preferable to tying it to an existing cpu id, if possible. -- 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 [-- Attachment #2: signature.asc --] [-- Type: application/pgp-signature, Size: 833 bytes --]
next prev parent reply other threads:[~2019-03-13 4:05 UTC|newest] Thread overview: 142+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-02-22 11:28 [PATCH v2 00/16] KVM: PPC: Book3S HV: add XIVE native exploitation mode Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-22 11:28 ` [PATCH v2 01/16] powerpc/xive: add OPAL extensions for the XIVE native exploitation support Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-24 23:42 ` David Gibson 2019-02-24 23:42 ` David Gibson 2019-02-25 3:50 ` Michael Ellerman 2019-02-25 3:50 ` Michael Ellerman 2019-02-25 10:11 ` Cédric Le Goater 2019-02-25 10:11 ` Cédric Le Goater 2019-02-26 4:21 ` David Gibson 2019-02-26 4:21 ` David Gibson 2019-03-12 18:25 ` Cédric Le Goater 2019-03-12 18:25 ` Cédric Le Goater 2019-02-22 11:28 ` [PATCH v2 02/16] KVM: PPC: Book3S HV: add a new KVM device for the XIVE native exploitation mode Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 0:08 ` David Gibson 2019-02-25 0:08 ` David Gibson 2019-03-12 11:14 ` Cédric Le Goater 2019-03-12 11:14 ` Cédric Le Goater 2019-02-22 11:28 ` [PATCH v2 03/16] KVM: PPC: Book3S HV: XIVE: introduce a new capability KVM_CAP_PPC_IRQ_XIVE Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 0:35 ` David Gibson 2019-02-25 0:35 ` David Gibson 2019-02-25 4:59 ` Paul Mackerras 2019-02-25 4:59 ` Paul Mackerras 2019-03-12 14:10 ` Cédric Le Goater 2019-03-12 14:10 ` Cédric Le Goater 2019-03-12 14:03 ` Cédric Le Goater 2019-03-12 14:03 ` Cédric Le Goater 2019-03-13 4:05 ` David Gibson [this message] 2019-03-13 4:05 ` David Gibson 2019-02-25 4:35 ` Paul Mackerras 2019-02-25 4:35 ` Paul Mackerras 2019-03-13 8:34 ` Cédric Le Goater 2019-03-13 8:34 ` Cédric Le Goater 2019-03-14 2:29 ` David Gibson 2019-03-14 2:29 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 04/16] KVM: PPC: Book3S HV: XIVE: add a control to initialize a source Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:10 ` David Gibson 2019-02-25 2:10 ` David Gibson 2019-02-26 4:25 ` Paul Mackerras 2019-02-26 4:25 ` Paul Mackerras 2019-02-26 23:20 ` David Gibson 2019-02-26 23:20 ` David Gibson 2019-03-12 15:19 ` Cédric Le Goater 2019-03-12 15:19 ` Cédric Le Goater 2019-03-14 2:15 ` David Gibson 2019-03-14 2:15 ` David Gibson 2019-02-25 5:30 ` Paul Mackerras 2019-02-25 5:30 ` Paul Mackerras 2019-02-22 11:28 ` [PATCH v2 05/16] KVM: PPC: Book3S HV: XIVE: add a control to configure " Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:21 ` David Gibson 2019-02-25 2:21 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 06/16] KVM: PPC: Book3S HV: XIVE: add controls for the EQ configuration Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:39 ` David Gibson 2019-02-25 2:39 ` David Gibson 2019-03-12 17:00 ` Cédric Le Goater 2019-03-12 17:00 ` Cédric Le Goater 2019-03-13 4:03 ` David Gibson 2019-03-13 4:03 ` David Gibson 2019-03-13 8:46 ` Cédric Le Goater 2019-03-13 8:46 ` Cédric Le Goater 2019-03-14 3:29 ` David Gibson 2019-03-14 3:29 ` David Gibson 2019-02-26 5:24 ` Paul Mackerras 2019-02-26 5:24 ` Paul Mackerras 2019-03-13 9:40 ` Cédric Le Goater 2019-03-13 9:40 ` Cédric Le Goater 2019-03-14 2:32 ` David Gibson 2019-03-14 2:32 ` David Gibson 2019-03-14 7:11 ` Cédric Le Goater 2019-03-14 7:11 ` Cédric Le Goater 2019-03-15 0:29 ` David Gibson 2019-03-15 0:29 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 07/16] KVM: PPC: Book3S HV: XIVE: add a global reset control Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:43 ` David Gibson 2019-02-25 2:43 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 08/16] KVM: PPC: Book3S HV: XIVE: add a control to sync the sources Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:45 ` David Gibson 2019-02-25 2:45 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 09/16] KVM: PPC: Book3S HV: XIVE: add a control to dirty the XIVE EQ pages Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 2:53 ` David Gibson 2019-02-25 2:53 ` David Gibson 2019-03-13 11:48 ` Cédric Le Goater 2019-03-13 11:48 ` Cédric Le Goater 2019-03-14 2:33 ` David Gibson 2019-03-14 2:33 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 10/16] KVM: PPC: Book3S HV: XIVE: add get/set accessors for the VP XIVE state Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 3:31 ` David Gibson 2019-02-25 3:31 ` David Gibson 2019-03-13 13:19 ` Cédric Le Goater 2019-03-13 13:19 ` Cédric Le Goater 2019-03-14 3:09 ` David Gibson 2019-03-14 3:09 ` David Gibson 2019-03-14 7:08 ` Cédric Le Goater 2019-03-14 7:08 ` Cédric Le Goater 2019-02-22 11:28 ` [PATCH v2 11/16] KVM: introduce a 'mmap' method for KVM devices Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 3:33 ` David Gibson 2019-02-25 3:33 ` David Gibson 2019-02-25 10:57 ` Cédric Le Goater 2019-02-25 10:57 ` Cédric Le Goater 2019-02-26 12:52 ` Paolo Bonzini 2019-02-26 12:52 ` Paolo Bonzini 2019-02-26 23:22 ` David Gibson 2019-02-26 23:22 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 12/16] KVM: PPC: Book3S HV: XIVE: add a TIMA mapping Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 3:42 ` David Gibson 2019-02-25 3:42 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 13/16] KVM: PPC: Book3S HV: XIVE: add a mapping for the source ESB pages Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 3:47 ` David Gibson 2019-02-25 3:47 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 14/16] KVM: PPC: Book3S HV: XIVE: add passthrough support Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 4:13 ` David Gibson 2019-02-25 4:13 ` David Gibson 2019-02-22 11:28 ` [PATCH v2 15/16] KVM: introduce a KVM_DESTROY_DEVICE ioctl Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 4:15 ` David Gibson 2019-02-25 4:15 ` David Gibson 2019-03-13 8:02 ` Cédric Le Goater 2019-03-13 8:02 ` Cédric Le Goater 2019-03-15 17:57 ` Paolo Bonzini 2019-03-15 17:57 ` Paolo Bonzini 2019-02-22 11:28 ` [PATCH v2 16/16] KVM: PPC: Book3S HV: XIVE: clear the vCPU interrupt presenters Cédric Le Goater 2019-02-22 11:28 ` Cédric Le Goater 2019-02-25 4:18 ` David Gibson 2019-02-25 4:18 ` David Gibson 2019-03-13 8:17 ` Cédric Le Goater 2019-03-13 8:17 ` Cédric Le Goater 2019-03-14 2:26 ` David Gibson 2019-03-14 2:26 ` David Gibson
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