From: Fuad Tabba <tabba@google.com>
To: Chao Peng <chao.p.peng@linux.intel.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-api@vger.kernel.org, linux-doc@vger.kernel.org,
qemu-devel@nongnu.org, Paolo Bonzini <pbonzini@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H . Peter Anvin" <hpa@zytor.com>,
Hugh Dickins <hughd@google.com>, Jeff Layton <jlayton@kernel.org>,
"J . Bruce Fields" <bfields@fieldses.org>,
Andrew Morton <akpm@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>, Mike Rapoport <rppt@kernel.org>,
Steven Price <steven.price@arm.com>,
"Maciej S . Szmigiero" <mail@maciej.szmigiero.name>,
Vlastimil Babka <vbabka@suse.cz>,
Vishal Annapurve <vannapurve@google.com>,
Yu Zhang <yu.c.zhang@linux.intel.com>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
luto@kernel.org, jun.nakajima@intel.com, dave.hansen@intel.com,
ak@linux.intel.com, david@redhat.com, aarcange@redhat.com,
ddutile@redhat.com, dhildenb@redhat.com,
Quentin Perret <qperret@google.com>,
Michael Roth <michael.roth@amd.com>,
mhocko@suse.com, Muchun Song <songmuchun@bytedance.com>,
wei.w.wang@intel.com
Subject: Re: [PATCH v8 5/8] KVM: Register/unregister the guest private memory regions
Date: Mon, 17 Oct 2022 11:15:02 +0100 [thread overview]
Message-ID: <CA+EHjTyGyGL+ox81=jdtoHERtHPV=P7wJub=3j7chdijyq-AgA@mail.gmail.com> (raw)
In-Reply-To: <20221012023516.GA3218049@chaop.bj.intel.com>
Hi,
> > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
> > > +#define KVM_MEM_ATTR_SHARED 0x0001
> > > +static int kvm_vm_ioctl_set_mem_attr(struct kvm *kvm, gpa_t gpa, gpa_t size,
> > > + bool is_private)
> > > +{
> >
> > I wonder if this ioctl should be implemented as an arch-specific
> > ioctl. In this patch it performs some actions that pKVM might not need
> > or might want to do differently.
>
> I think it's doable. We can provide the mem_attr_array kind thing in
> common code and let arch code decide to use it or not. Currently
> mem_attr_array is defined in the struct kvm, if those bytes are
> unnecessary for pKVM it can even be moved to arch definition, but that
> also loses the potential code sharing for confidential usages in other
> non-architectures, e.g. if ARM also supports such usage. Or it can be
> provided through a different CONFIG_ instead of
> CONFIG_HAVE_KVM_PRIVATE_MEM.
This sounds good. Thank you.
/fuad
> Thanks,
> Chao
> >
> > pKVM tracks the sharing status in the stage-2 page table's software
> > bits, so it can avoid the overhead of using mem_attr_array.
> >
> > Also, this ioctl calls kvm_zap_gfn_range(), as does the invalidation
> > notifier (introduced in patch 8). For pKVM, the kind of zapping (or
> > the information conveyed to the hypervisor) might need to be different
> > depending on the cause; whether it's invalidation or change of sharing
> > status.
>
> >
> > Thanks,
> > /fuad
> >
> >
> > > + gfn_t start, end;
> > > + unsigned long index;
> > > + void *entry;
> > > + int r;
> > > +
> > > + if (size == 0 || gpa + size < gpa)
> > > + return -EINVAL;
> > > + if (gpa & (PAGE_SIZE - 1) || size & (PAGE_SIZE - 1))
> > > + return -EINVAL;
> > > +
> > > + start = gpa >> PAGE_SHIFT;
> > > + end = (gpa + size - 1 + PAGE_SIZE) >> PAGE_SHIFT;
> > > +
> > > + /*
> > > + * Guest memory defaults to private, kvm->mem_attr_array only stores
> > > + * shared memory.
> > > + */
> > > + entry = is_private ? NULL : xa_mk_value(KVM_MEM_ATTR_SHARED);
> > > +
> > > + for (index = start; index < end; index++) {
> > > + r = xa_err(xa_store(&kvm->mem_attr_array, index, entry,
> > > + GFP_KERNEL_ACCOUNT));
> > > + if (r)
> > > + goto err;
> > > + }
> > > +
> > > + kvm_zap_gfn_range(kvm, start, end);
> > > +
> > > + return r;
> > > +err:
> > > + for (; index > start; index--)
> > > + xa_erase(&kvm->mem_attr_array, index);
> > > + return r;
> > > +}
> > > +#endif /* CONFIG_HAVE_KVM_PRIVATE_MEM */
> > > +
> > > #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
> > > static int kvm_pm_notifier_call(struct notifier_block *bl,
> > > unsigned long state,
> > > @@ -1165,6 +1206,9 @@ static struct kvm *kvm_create_vm(unsigned long type, const char *fdname)
> > > spin_lock_init(&kvm->mn_invalidate_lock);
> > > rcuwait_init(&kvm->mn_memslots_update_rcuwait);
> > > xa_init(&kvm->vcpu_array);
> > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
> > > + xa_init(&kvm->mem_attr_array);
> > > +#endif
> > >
> > > INIT_LIST_HEAD(&kvm->gpc_list);
> > > spin_lock_init(&kvm->gpc_lock);
> > > @@ -1338,6 +1382,9 @@ static void kvm_destroy_vm(struct kvm *kvm)
> > > kvm_free_memslots(kvm, &kvm->__memslots[i][0]);
> > > kvm_free_memslots(kvm, &kvm->__memslots[i][1]);
> > > }
> > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
> > > + xa_destroy(&kvm->mem_attr_array);
> > > +#endif
> > > cleanup_srcu_struct(&kvm->irq_srcu);
> > > cleanup_srcu_struct(&kvm->srcu);
> > > kvm_arch_free_vm(kvm);
> > > @@ -1541,6 +1588,11 @@ static void kvm_replace_memslot(struct kvm *kvm,
> > > }
> > > }
> > >
> > > +bool __weak kvm_arch_has_private_mem(struct kvm *kvm)
> > > +{
> > > + return false;
> > > +}
> > > +
> > > static int check_memory_region_flags(const struct kvm_user_mem_region *mem)
> > > {
> > > u32 valid_flags = KVM_MEM_LOG_DIRTY_PAGES;
> > > @@ -4703,6 +4755,24 @@ static long kvm_vm_ioctl(struct file *filp,
> > > r = kvm_vm_ioctl_set_memory_region(kvm, &mem);
> > > break;
> > > }
> > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
> > > + case KVM_MEMORY_ENCRYPT_REG_REGION:
> > > + case KVM_MEMORY_ENCRYPT_UNREG_REGION: {
> > > + struct kvm_enc_region region;
> > > + bool set = ioctl == KVM_MEMORY_ENCRYPT_REG_REGION;
> > > +
> > > + if (!kvm_arch_has_private_mem(kvm))
> > > + goto arch_vm_ioctl;
> > > +
> > > + r = -EFAULT;
> > > + if (copy_from_user(®ion, argp, sizeof(region)))
> > > + goto out;
> > > +
> > > + r = kvm_vm_ioctl_set_mem_attr(kvm, region.addr,
> > > + region.size, set);
> > > + break;
> > > + }
> > > +#endif
> > > case KVM_GET_DIRTY_LOG: {
> > > struct kvm_dirty_log log;
> > >
> > > @@ -4856,6 +4926,9 @@ static long kvm_vm_ioctl(struct file *filp,
> > > r = kvm_vm_ioctl_get_stats_fd(kvm);
> > > break;
> > > default:
> > > +#ifdef CONFIG_HAVE_KVM_PRIVATE_MEM
> > > +arch_vm_ioctl:
> > > +#endif
> > > r = kvm_arch_vm_ioctl(filp, ioctl, arg);
> > > }
> > > out:
> > > --
> > > 2.25.1
> > >
next prev parent reply other threads:[~2022-10-17 10:16 UTC|newest]
Thread overview: 97+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-15 14:29 [PATCH v8 0/8] KVM: mm: fd-based approach for supporting KVM Chao Peng
2022-09-15 14:29 ` [PATCH v8 1/8] mm/memfd: Introduce userspace inaccessible memfd Chao Peng
2022-09-19 9:12 ` David Hildenbrand
2022-09-19 19:10 ` Sean Christopherson
2022-09-21 21:10 ` Andy Lutomirski
2022-09-22 13:23 ` Wang, Wei W
2022-09-23 15:20 ` Fuad Tabba
2022-09-23 15:19 ` Fuad Tabba
2022-09-26 14:23 ` Chao Peng
2022-09-26 15:51 ` Fuad Tabba
2022-09-27 22:47 ` Sean Christopherson
2022-09-30 16:19 ` Fuad Tabba
2022-10-13 13:34 ` Chao Peng
2022-10-17 10:31 ` Fuad Tabba
2022-10-17 14:58 ` Chao Peng
2022-10-17 19:05 ` Fuad Tabba
2022-10-19 13:30 ` Chao Peng
2022-10-18 0:33 ` Sean Christopherson
2022-10-19 15:04 ` Fuad Tabba
2022-09-23 0:58 ` Kirill A . Shutemov
2022-09-26 10:35 ` David Hildenbrand
2022-09-26 14:48 ` Kirill A. Shutemov
2022-09-26 14:53 ` David Hildenbrand
2022-09-27 23:23 ` Sean Christopherson
2022-09-28 13:36 ` Kirill A. Shutemov
2022-09-22 13:26 ` Wang, Wei W
2022-09-22 19:49 ` Sean Christopherson
2022-09-23 0:53 ` Kirill A . Shutemov
2022-09-23 15:20 ` Fuad Tabba
2022-09-30 16:14 ` Fuad Tabba
2022-09-30 16:23 ` Kirill A . Shutemov
2022-10-03 7:33 ` Fuad Tabba
2022-10-03 11:01 ` Kirill A. Shutemov
2022-10-04 15:39 ` Fuad Tabba
2022-10-06 8:50 ` Fuad Tabba
2022-10-06 13:04 ` Kirill A. Shutemov
2022-10-17 13:00 ` Vlastimil Babka
2022-10-17 16:19 ` Kirill A . Shutemov
2022-10-17 16:39 ` Gupta, Pankaj
2022-10-17 21:56 ` Kirill A . Shutemov
2022-10-18 13:42 ` Vishal Annapurve
2022-10-19 15:32 ` Kirill A . Shutemov
2022-10-20 10:50 ` Vishal Annapurve
2022-10-21 13:54 ` Chao Peng
2022-10-21 16:53 ` Sean Christopherson
2022-10-19 12:23 ` Vishal Annapurve
2022-10-21 13:47 ` Chao Peng
2022-10-21 16:18 ` Sean Christopherson
2022-10-24 14:59 ` Kirill A . Shutemov
2022-10-24 15:26 ` David Hildenbrand
2022-11-03 16:27 ` Vishal Annapurve
2022-09-15 14:29 ` [PATCH v8 2/8] KVM: Extend the memslot to support fd-based private memory Chao Peng
2022-09-16 9:14 ` Bagas Sanjaya
2022-09-16 9:53 ` Chao Peng
2022-09-26 10:26 ` Fuad Tabba
2022-09-26 14:04 ` Chao Peng
2022-09-29 22:45 ` Isaku Yamahata
2022-09-29 23:22 ` Sean Christopherson
2022-10-05 13:04 ` Jarkko Sakkinen
2022-10-05 22:05 ` Jarkko Sakkinen
2022-10-06 9:00 ` Fuad Tabba
2022-10-06 14:58 ` Jarkko Sakkinen
2022-10-06 15:07 ` Jarkko Sakkinen
2022-10-06 15:34 ` Sean Christopherson
2022-10-07 11:14 ` Jarkko Sakkinen
2022-10-07 14:58 ` Sean Christopherson
2022-10-07 21:54 ` Jarkko Sakkinen
2022-10-08 16:15 ` Jarkko Sakkinen
2022-10-08 17:35 ` Jarkko Sakkinen
2022-10-10 8:25 ` Chao Peng
2022-10-12 8:14 ` Jarkko Sakkinen
2022-09-15 14:29 ` [PATCH v8 3/8] KVM: Add KVM_EXIT_MEMORY_FAULT exit Chao Peng
2022-09-16 9:17 ` Bagas Sanjaya
2022-09-16 9:54 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 4/8] KVM: Use gfn instead of hva for mmu_notifier_retry Chao Peng
2022-09-15 14:29 ` [PATCH v8 5/8] KVM: Register/unregister the guest private memory regions Chao Peng
2022-09-26 10:36 ` Fuad Tabba
2022-09-26 14:07 ` Chao Peng
2022-10-11 9:48 ` Fuad Tabba
2022-10-12 2:35 ` Chao Peng
2022-10-17 10:15 ` Fuad Tabba [this message]
2022-10-17 22:17 ` Sean Christopherson
2022-10-19 13:23 ` Chao Peng
2022-10-19 15:02 ` Fuad Tabba
2022-10-19 16:09 ` Sean Christopherson
2022-10-19 18:32 ` Fuad Tabba
2022-09-15 14:29 ` [PATCH v8 6/8] KVM: Update lpage info when private/shared memory are mixed Chao Peng
2022-09-29 16:52 ` Isaku Yamahata
2022-09-30 8:59 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 7/8] KVM: Handle page fault for private memory Chao Peng
2022-10-14 18:57 ` Sean Christopherson
2022-10-17 14:48 ` Chao Peng
2022-09-15 14:29 ` [PATCH v8 8/8] KVM: Enable and expose KVM_MEM_PRIVATE Chao Peng
2022-10-04 14:55 ` Jarkko Sakkinen
2022-10-10 8:31 ` Chao Peng
2022-10-06 8:55 ` Fuad Tabba
2022-10-10 8:33 ` Chao Peng
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