From: Ashish Kalra <ashish.kalra@amd.com>
To: Tom Lendacky <thomas.lendacky@amd.com>
Cc: pbonzini@redhat.com, tglx@linutronix.de, mingo@redhat.com,
hpa@zytor.com, rkrcmar@redhat.com, joro@8bytes.org, bp@suse.de,
x86@kernel.org, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, srutherford@google.com,
seanjc@google.com, venu.busireddy@oracle.com,
brijesh.singh@amd.com
Subject: Re: [PATCH v10 10/16] KVM: x86: Introduce KVM_GET_SHARED_PAGES_LIST ioctl
Date: Thu, 4 Feb 2021 16:34:52 +0000 [thread overview]
Message-ID: <20210204163452.GA25878@ashkalra_ubuntu_server> (raw)
In-Reply-To: <6cb9bd69-6217-9923-3161-b4163646c1e2@amd.com>
Hello Tom,
On Thu, Feb 04, 2021 at 10:14:37AM -0600, Tom Lendacky wrote:
> On 2/3/21 6:39 PM, Ashish Kalra wrote:
> > From: Brijesh Singh <brijesh.singh@amd.com>
> >
> > The ioctl is used to retrieve a guest's shared pages list.
> >
>
> ...
>
> > +int svm_get_shared_pages_list(struct kvm *kvm,
> > + struct kvm_shared_pages_list *list)
> > +{
> > + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
> > + struct shared_region_array_entry *array;
> > + struct shared_region *pos;
> > + int ret, nents = 0;
> > + unsigned long sz;
> > +
> > + if (!sev_guest(kvm))
> > + return -ENOTTY;
> > +
> > + if (!list->size)
> > + return -EINVAL;
> > +
> > + if (!sev->shared_pages_list_count)
> > + return put_user(0, list->pnents);
> > +
> > + sz = sev->shared_pages_list_count * sizeof(struct shared_region_array_entry);
> > + if (sz > list->size)
> > + return -E2BIG;
> > +
> > + array = kmalloc(sz, GFP_KERNEL);
> > + if (!array)
> > + return -ENOMEM;
> > +
> > + mutex_lock(&kvm->lock);
>
> I think this lock needs to be taken before the memory size is calculated. If
> the list is expanded after obtaining the size and before taking the lock,
> you will run off the end of the array.
>
Yes, as the page encryption status hcalls can happen simultaneously to
this ioctl, therefore this is an issue, so i will take the lock before
the memory size is calculated.
Thanks,
Ashish
>
> > + list_for_each_entry(pos, &sev->shared_pages_list, list) {
> > + array[nents].gfn_start = pos->gfn_start;
> > + array[nents++].gfn_end = pos->gfn_end;
> > + }
> > + mutex_unlock(&kvm->lock);
> > +
> > + ret = -EFAULT;
> > + if (copy_to_user(list->buffer, array, sz))
> > + goto out;
> > + if (put_user(nents, list->pnents))
> > + goto out;
> > + ret = 0;
> > +out:
> > + kfree(array);
> > + return ret;
> > +}
> > +
next prev parent reply other threads:[~2021-02-04 16:37 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-04 0:35 [PATCH v10 00/17] Add AMD SEV guest live migration support Ashish Kalra
2021-02-04 0:36 ` [PATCH v10 01/16] KVM: SVM: Add KVM_SEV SEND_START command Ashish Kalra
2021-02-04 0:36 ` [PATCH v10 02/16] KVM: SVM: Add KVM_SEND_UPDATE_DATA command Ashish Kalra
2021-02-04 0:37 ` [PATCH v10 03/16] KVM: SVM: Add KVM_SEV_SEND_FINISH command Ashish Kalra
2021-02-04 0:37 ` [PATCH v10 04/16] KVM: SVM: Add support for KVM_SEV_RECEIVE_START command Ashish Kalra
2021-02-04 0:37 ` [PATCH v10 05/16] KVM: SVM: Add KVM_SEV_RECEIVE_UPDATE_DATA command Ashish Kalra
2021-02-04 0:37 ` [PATCH v10 06/16] KVM: SVM: Add KVM_SEV_RECEIVE_FINISH command Ashish Kalra
2021-02-04 0:38 ` [PATCH v10 07/16] KVM: x86: Add AMD SEV specific Hypercall3 Ashish Kalra
2021-02-04 0:38 ` [PATCH v10 08/16] KVM: X86: Introduce KVM_HC_PAGE_ENC_STATUS hypercall Ashish Kalra
2021-02-04 16:03 ` Tom Lendacky
2021-02-05 1:44 ` Steve Rutherford
2021-02-05 3:32 ` Ashish Kalra
2021-02-04 0:39 ` [PATCH v10 09/16] mm: x86: Invoke hypercall when page encryption status is changed Ashish Kalra
2021-02-04 0:39 ` [PATCH v10 10/16] KVM: x86: Introduce KVM_GET_SHARED_PAGES_LIST ioctl Ashish Kalra
2021-02-04 16:14 ` Tom Lendacky
2021-02-04 16:34 ` Ashish Kalra [this message]
2021-02-17 1:03 ` Sean Christopherson
2021-02-17 14:00 ` Kalra, Ashish
2021-02-17 16:13 ` Sean Christopherson
2021-02-18 6:48 ` Kalra, Ashish
2021-02-18 16:39 ` Sean Christopherson
2021-02-18 17:05 ` Kalra, Ashish
2021-02-18 17:50 ` Sean Christopherson
2021-02-18 18:32 ` Kalra, Ashish
2021-02-24 17:51 ` Ashish Kalra
2021-02-24 18:22 ` Sean Christopherson
2021-02-25 20:20 ` Ashish Kalra
2021-02-25 22:59 ` Steve Rutherford
2021-02-25 23:24 ` Steve Rutherford
2021-02-26 14:04 ` Ashish Kalra
2021-02-26 17:44 ` Sean Christopherson
2021-03-02 14:55 ` Ashish Kalra
2021-03-02 15:15 ` Ashish Kalra
2021-03-03 18:54 ` Will Deacon
2021-03-03 19:32 ` Ashish Kalra
2021-03-09 19:10 ` Ashish Kalra
2021-03-11 18:14 ` Ashish Kalra
2021-03-11 20:48 ` Steve Rutherford
2021-03-19 17:59 ` Ashish Kalra
2021-04-02 1:40 ` Steve Rutherford
2021-04-02 11:09 ` Ashish Kalra
2021-03-08 10:40 ` Ashish Kalra
2021-03-08 19:51 ` Sean Christopherson
2021-03-08 21:05 ` Ashish Kalra
2021-03-08 21:11 ` Brijesh Singh
2021-03-08 21:32 ` Ashish Kalra
2021-03-08 21:51 ` Steve Rutherford
2021-03-09 19:42 ` Sean Christopherson
2021-03-10 3:42 ` Kalra, Ashish
2021-03-10 3:47 ` Steve Rutherford
2021-03-08 21:48 ` Steve Rutherford
2021-02-17 1:06 ` Sean Christopherson
2021-02-04 0:39 ` [PATCH v10 11/16] KVM: x86: Introduce KVM_SET_SHARED_PAGES_LIST ioctl Ashish Kalra
2021-02-04 0:39 ` [PATCH v10 12/16] KVM: x86: Introduce new KVM_FEATURE_SEV_LIVE_MIGRATION feature & Custom MSR Ashish Kalra
2021-02-05 0:56 ` Steve Rutherford
2021-02-05 3:07 ` Ashish Kalra
2021-02-06 2:54 ` Steve Rutherford
2021-02-06 4:49 ` Ashish Kalra
2021-02-06 5:46 ` Ashish Kalra
2021-02-06 13:56 ` Ashish Kalra
2021-02-08 0:28 ` Ashish Kalra
2021-02-08 22:50 ` Steve Rutherford
2021-02-10 20:36 ` Ashish Kalra
2021-02-10 22:01 ` Steve Rutherford
2021-02-10 22:05 ` Steve Rutherford
2021-02-16 23:20 ` Sean Christopherson
2021-02-04 0:40 ` [PATCH v10 13/16] EFI: Introduce the new AMD Memory Encryption GUID Ashish Kalra
2021-02-04 0:40 ` [PATCH v10 14/16] KVM: x86: Add guest support for detecting and enabling SEV Live Migration feature Ashish Kalra
2021-02-18 17:56 ` Sean Christopherson
2021-02-04 0:40 ` [PATCH v10 15/16] KVM: x86: Add kexec support for SEV Live Migration Ashish Kalra
2021-02-04 4:10 ` kernel test robot
2021-02-04 0:40 ` [PATCH v10 16/16] KVM: SVM: Bypass DBG_DECRYPT API calls for unencrypted guest memory Ashish Kalra
2021-02-09 6:23 ` kernel test robot
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