From: Zhi Wang <zhi.wang.linux@gmail.com>
To: Michael Roth <michael.roth@amd.com>
Cc: <kvm@vger.kernel.org>, <linux-coco@lists.linux.dev>,
<linux-mm@kvack.org>, <linux-crypto@vger.kernel.org>,
<x86@kernel.org>, <linux-kernel@vger.kernel.org>,
<tglx@linutronix.de>, <mingo@redhat.com>, <jroedel@suse.de>,
<thomas.lendacky@amd.com>, <hpa@zytor.com>, <ardb@kernel.org>,
<pbonzini@redhat.com>, <seanjc@google.com>, <vkuznets@redhat.com>,
<jmattson@google.com>, <luto@kernel.org>,
<dave.hansen@linux.intel.com>, <slp@redhat.com>,
<pgonda@google.com>, <peterz@infradead.org>,
<srinivas.pandruvada@linux.intel.com>, <rientjes@google.com>,
<dovmurik@linux.ibm.com>, <tobin@ibm.com>, <bp@alien8.de>,
<vbabka@suse.cz>, <kirill@shutemov.name>, <ak@linux.intel.com>,
<tony.luck@intel.com>, <marcorr@google.com>,
<sathyanarayanan.kuppuswamy@linux.intel.com>,
<alpergun@google.com>, <dgilbert@redhat.com>, <jarkko@kernel.org>,
<ashish.kalra@amd.com>, <nikunj.dadhania@amd.com>,
Vishal Annapurve <vannapurve@google.com>
Subject: Re: [PATCH RFC v8 04/56] KVM: Add HVA range operator
Date: Tue, 4 Apr 2023 17:40:48 +0300 [thread overview]
Message-ID: <20230404174048.00005ef9.zhi.wang.linux@gmail.com> (raw)
In-Reply-To: <20230327003444.lqfrididd4gavomb@amd.com>
On Sun, 26 Mar 2023 19:34:44 -0500
Michael Roth <michael.roth@amd.com> wrote:
> On Mon, Feb 20, 2023 at 11:37:09PM +0200, Zhi Wang wrote:
> > On Mon, 20 Feb 2023 12:37:55 -0600
> > Michael Roth <michael.roth@amd.com> wrote:
> >
> > > From: Vishal Annapurve <vannapurve@google.com>
> > >
> > > Introduce HVA range operator so that other KVM subsystems
> > > can operate on HVA range.
> > >
> > > Signed-off-by: Vishal Annapurve <vannapurve@google.com>
> > > [mdr: minor checkpatch alignment fixups]
> > > Signed-off-by: Michael Roth <michael.roth@amd.com>
> > > ---
> > > include/linux/kvm_host.h | 6 +++++
> > > virt/kvm/kvm_main.c | 48 ++++++++++++++++++++++++++++++++++++++++
> > > 2 files changed, 54 insertions(+)
> > >
> > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> > > index 4d542060cd93..c615650ed256 100644
> > > --- a/include/linux/kvm_host.h
> > > +++ b/include/linux/kvm_host.h
> > > @@ -1402,6 +1402,12 @@ void kvm_mmu_invalidate_begin(struct kvm *kvm);
> > > void kvm_mmu_invalidate_range_add(struct kvm *kvm, gfn_t start, gfn_t end);
> > > void kvm_mmu_invalidate_end(struct kvm *kvm);
> > >
> > > +typedef int (*kvm_hva_range_op_t)(struct kvm *kvm,
> > > + struct kvm_gfn_range *range, void *data);
> > > +
> > > +int kvm_vm_do_hva_range_op(struct kvm *kvm, unsigned long hva_start,
> > > + unsigned long hva_end, kvm_hva_range_op_t handler, void *data);
> > > +
> > > long kvm_arch_dev_ioctl(struct file *filp,
> > > unsigned int ioctl, unsigned long arg);
> > > long kvm_arch_vcpu_ioctl(struct file *filp,
> > > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> > > index f7e00593cc5d..4ccd655dd5af 100644
> > > --- a/virt/kvm/kvm_main.c
> > > +++ b/virt/kvm/kvm_main.c
> > > @@ -642,6 +642,54 @@ static __always_inline int __kvm_handle_hva_range(struct kvm *kvm,
> > > return (int)ret;
> > > }
> > >
> >
> > Below function seems a reduced duplicate of __kvm_handle_hva_range()
> > in virt/kvm/kvm_main.c. It would be nice to factor __kvm_handle_hva_range().
>
> A few differences make it difficult to refactor this clearly:
>
> - This handler is mainly used for loading initial contents into guest
> image before booting and doesn't rely on the MMU lock being held. It
> also *can't* be called with MMU lock held because it suffers from the
> same issue with mem_attr_update() hook where it needs to take a
> mutex as part of unmapping from directmap when transitioning page to
> private state in RMP table
> - This handler wants to return an error code, as opposed to existing
> handlers which return a true/false values which are passed along to
> MMU notifier call-site and handled differently.
> - This handler wants to terminate iterating through memslots as soon
> as it encounters the first failure, whereas the existing handlers
> expect to be called for each slot regardless of return value.
>
> So it's a pretty different use-case that adds enough complexity to
> __kvm_handle_hva_range() that it might need be worth refactoring it,
> since it complicates some bits that are closely tied to dealing with
> invalidations where the extra complexity probably needs to be
> well-warranted.
>
> I took a stab at it here for reference, but even with what seems to be
> the minimal set of changes it doesn't save on any code and ultimately I
> think it makes it harder to make sense of what going on:
>
> https://github.com/mdroth/linux/commit/976c5fb708f7babe899fd80e27e19f8ba3f6818d
>
> Is there a better approach?
>
Those requirements looks pretty suitable for kvm_handle_hva_range(). Guess
we just need to extend the iterator a little bit.
My ideas:
1) Add a lock flag in struct kvm_hva_range to indicate if kvm_lock is required
or not during the iteration. Check the flag with if (!locked && hva_range.need_lock). Then the unlock part can be left un-touched.
2) Add an error code in struct kvm_gfn_range, the handler can set it so that __kvm_handle_hva_range() can check gfn_range.err after ret|= handler(xxx);
If the err is set, bail out.
3) Return the gfn_range.err to the caller. The caller can decide how to convert
it (to boolean or keep it)
4) Set hva_range.need_lock in the existing and the new caller.
How about this?
> Thanks,
>
> -Mike
>
> >
> > > +int kvm_vm_do_hva_range_op(struct kvm *kvm, unsigned long hva_start,
> > > + unsigned long hva_end, kvm_hva_range_op_t handler, void *data)
> > > +{
> > > + int ret = 0;
> > > + struct kvm_gfn_range gfn_range;
> > > + struct kvm_memory_slot *slot;
> > > + struct kvm_memslots *slots;
> > > + int i, idx;
> > > +
> > > + if (WARN_ON_ONCE(hva_end <= hva_start))
> > > + return -EINVAL;
> > > +
> > > + idx = srcu_read_lock(&kvm->srcu);
> > > +
> > > + for (i = 0; i < kvm_arch_nr_memslot_as_ids(kvm); i++) {
> > > + struct interval_tree_node *node;
> > > +
> > > + slots = __kvm_memslots(kvm, i);
> > > + kvm_for_each_memslot_in_hva_range(node, slots,
> > > + hva_start, hva_end - 1) {
> > > + unsigned long start, end;
> > > +
> > > + slot = container_of(node, struct kvm_memory_slot,
> > > + hva_node[slots->node_idx]);
> > > + start = max(hva_start, slot->userspace_addr);
> > > + end = min(hva_end, slot->userspace_addr +
> > > + (slot->npages << PAGE_SHIFT));
> > > +
> > > + /*
> > > + * {gfn(page) | page intersects with [hva_start, hva_end)} =
> > > + * {gfn_start, gfn_start+1, ..., gfn_end-1}.
> > > + */
> > > + gfn_range.start = hva_to_gfn_memslot(start, slot);
> > > + gfn_range.end = hva_to_gfn_memslot(end + PAGE_SIZE - 1, slot);
> > > + gfn_range.slot = slot;
> > > +
> > > + ret = handler(kvm, &gfn_range, data);
> > > + if (ret)
> > > + goto e_ret;
> > > + }
> > > + }
> > > +
> > > +e_ret:
> > > + srcu_read_unlock(&kvm->srcu, idx);
> > > +
> > > + return ret;
> > > +}
> > > +
> > > static __always_inline int kvm_handle_hva_range(struct mmu_notifier *mn,
> > > unsigned long start,
> > > unsigned long end,
> >
next prev parent reply other threads:[~2023-04-04 14:40 UTC|newest]
Thread overview: 147+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-20 18:37 [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 01/56] KVM: x86: Add 'fault_is_private' x86 op Michael Roth
2023-03-01 10:25 ` Zhi Wang
2023-03-18 4:51 ` Isaku Yamahata
2023-03-20 17:46 ` Michael Roth
2023-03-18 4:53 ` Isaku Yamahata
2023-02-20 18:37 ` [PATCH RFC v8 02/56] KVM: x86: Add 'update_mem_attr' " Michael Roth
2023-03-18 4:56 ` Isaku Yamahata
2023-03-20 18:05 ` Michael Roth
2023-03-21 11:21 ` Zhi Wang
2023-03-22 1:58 ` Michael Roth
2023-03-23 18:17 ` Zhi Wang
2023-03-28 4:36 ` Michael Roth
2023-03-28 23:00 ` Zhi Wang
2023-03-29 23:50 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 03/56] KVM: x86: Add platform hooks for private memory invalidations Michael Roth
2023-03-18 5:13 ` Isaku Yamahata
2023-03-20 18:09 ` Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 04/56] KVM: Add HVA range operator Michael Roth
2023-02-20 21:37 ` Zhi Wang
2023-03-27 0:34 ` Michael Roth
2023-04-04 14:40 ` Zhi Wang [this message]
2023-02-20 18:37 ` [PATCH RFC v8 05/56] KVM: SEV: Require KVM_PROTECTED_VM when AMD_MEM_ENCRYPT is enabled Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 06/56] KVM: Split out memory attribute xarray updates to helper function Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 07/56] KVM: SEV: Populate private memory fd during LAUNCH_UPDATE_DATA Michael Roth
2023-02-20 18:37 ` [PATCH RFC v8 08/56] KVM: SEV: Rename sev_{pin,unpin}_memory Michael Roth
2023-03-03 14:00 ` Vlastimil Babka
2023-03-06 11:01 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 09/56] KVM: SEV: Handle memory backed by restricted memfd Michael Roth
2023-03-03 14:05 ` Vlastimil Babka
2023-03-06 11:03 ` Nikunj A. Dadhania
2023-02-20 18:38 ` [PATCH RFC v8 10/56] x86/cpufeatures: Add SEV-SNP CPU feature Michael Roth
2023-02-21 21:21 ` Sathyanarayanan Kuppuswamy
2023-02-22 23:27 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 11/56] x86/sev: Add the host SEV-SNP initialization support Michael Roth
2023-02-20 20:12 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 12/56] x86/sev: Add RMP entry lookup helpers Michael Roth
2023-03-03 15:28 ` Vlastimil Babka
2023-03-29 22:59 ` Michael Roth
2023-04-20 16:31 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 13/56] x86/fault: Add helper for dumping RMP entries Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 14/56] x86/sev: Add helper functions for RMPUPDATE and PSMASH instruction Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 15/56] x86/sev: Invalidate pages from the direct map when adding them to the RMP table Michael Roth
2023-03-01 12:07 ` Tom Dohrmann
2023-03-01 16:15 ` Dave Hansen
2023-03-28 22:12 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 16/56] x86/traps: Define RMP violation #PF error code Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 17/56] x86/fault: Add support to handle the RMP fault for user address Michael Roth
2023-03-01 16:21 ` Dave Hansen
2023-03-28 23:31 ` Michael Roth
2023-04-11 18:27 ` Dave Hansen
2023-03-03 15:31 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 18/56] x86/fault: fix handle_split_page_fault() to work with memfd backed pages Michael Roth
2023-02-20 19:57 ` Hugh Dickins
2023-02-20 20:31 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 19/56] x86/fault: Return pfn from dump_pagetable() for SEV-specific fault handling Michael Roth
2023-02-20 21:13 ` Zhi Wang
2023-02-28 10:53 ` Wu Zongyong
2023-02-20 18:38 ` [PATCH RFC v8 20/56] crypto:ccp: Define the SEV-SNP commands Michael Roth
2023-04-17 14:54 ` Sabin Rapan
2023-02-20 18:38 ` [PATCH RFC v8 21/56] crypto: ccp: Add support to initialize the AMD-SP for SEV-SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 22/56] crypto:ccp: Provide API to issue SEV and SNP commands Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 23/56] crypto: ccp: Introduce snp leaked pages list Michael Roth
2023-03-03 15:54 ` Vlastimil Babka
2023-02-20 18:38 ` [PATCH RFC v8 24/56] crypto: ccp: Handle the legacy TMR allocation when SNP is enabled Michael Roth
2023-02-21 9:28 ` Zhi Wang
2023-02-21 15:31 ` Kalra, Ashish
2023-02-21 21:15 ` Zhi Wang
2023-02-21 22:06 ` Kalra, Ashish
2023-02-20 18:38 ` [PATCH RFC v8 25/56] crypto: ccp: Handle the legacy SEV command " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 26/56] crypto: ccp: Add the SNP_PLATFORM_STATUS command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 27/56] crypto: ccp: Add the SNP_{SET,GET}_EXT_CONFIG command Michael Roth
2023-02-22 12:32 ` Zhi Wang
2023-02-22 16:50 ` Tom Lendacky
2023-02-22 22:43 ` Kalra, Ashish
2023-02-23 6:38 ` Zhi Wang
2023-02-23 14:19 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 28/56] crypto: ccp: Provide APIs to query extended attestation report Michael Roth
2023-02-22 20:24 ` Zhi Wang
2023-02-22 22:35 ` Kalra, Ashish
2023-02-23 8:14 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 29/56] KVM: SVM: Add support to handle AP reset MSR protocol Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 30/56] KVM: SVM: Provide the Hypervisor Feature support VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 31/56] KVM: SVM: Make AVIC backing, VMSA and VMCB memory allocation SNP safe Michael Roth
2023-02-22 20:42 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 32/56] KVM: SVM: Add initial SEV-SNP support Michael Roth
2023-02-23 17:46 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 33/56] KVM: SVM: Add KVM_SNP_INIT command Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 34/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_START command Michael Roth
2023-02-23 21:41 ` Zhi Wang
2023-02-24 16:22 ` Tom Lendacky
2023-04-26 17:06 ` Sabin Rapan
2023-04-26 18:02 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 35/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_UPDATE command Michael Roth
2023-02-24 11:55 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 36/56] KVM: SVM: Add KVM_SEV_SNP_LAUNCH_FINISH command Michael Roth
2023-03-24 14:40 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 37/56] KVM: X86: Keep the NPT and RMP page level in sync Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 38/56] KVM: x86: Define RMP page fault error bits for #NPF Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 39/56] KVM: SVM: Add support to handle GHCB GPA register VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 40/56] KVM: SVM: Add KVM_EXIT_VMGEXIT Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 41/56] KVM: SVM: Add support to handle MSR based Page State Change VMGEXIT Michael Roth
2023-02-24 15:06 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 42/56] KVM: SVM: Add support to handle " Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 43/56] KVM: x86: Export the kvm_zap_gfn_range() for the SNP use Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 44/56] KVM: SVM: Add support to handle the RMP nested page fault Michael Roth
2023-02-28 19:11 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 45/56] KVM: SVM: Provide support for SNP_GUEST_REQUEST NAE event Michael Roth
2023-02-24 11:01 ` Alexander Graf
2023-02-28 19:34 ` Zhi Wang
2023-04-17 13:05 ` Alexander Graf
2023-02-20 18:38 ` [PATCH RFC v8 46/56] KVM: SVM: Use a VMSA physical address variable for populating VMCB Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 47/56] KVM: SVM: Support SEV-SNP AP Creation NAE event Michael Roth
2023-02-24 12:37 ` Alexander Graf
2023-02-28 20:47 ` Zhi Wang
2023-03-01 21:14 ` Alexander Graf
2023-04-05 0:54 ` Michael Roth
2023-04-04 22:48 ` Michael Roth
2023-04-05 15:20 ` Tom Lendacky
2023-02-20 18:38 ` [PATCH RFC v8 48/56] KVM: SVM: Add SNP-specific handling for memory attribute updates Michael Roth
2023-03-01 23:37 ` Dave Hansen
2023-04-05 23:48 ` Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 49/56] KVM: SVM: Implement .fault_is_private callback for SNP Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 50/56] KVM: SEV: Handle restricted memory invalidations " Michael Roth
2023-03-01 10:41 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 51/56] KVM: SVM: Add module parameter to enable the SEV-SNP Michael Roth
2023-03-01 10:45 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 52/56] ccp: Add support to decrypt the page Michael Roth
2023-03-01 21:20 ` Zhi Wang
2023-03-02 5:59 ` Dov Murik
2023-03-02 14:33 ` Tom Lendacky
2023-03-02 21:11 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 53/56] KVM: SVM: Make VMSAVE target area memory allocation SNP safe Michael Roth
2023-03-01 21:23 ` Zhi Wang
2023-02-20 18:38 ` [PATCH RFC v8 54/56] x86/sev: Add KVM commands for instance certs Michael Roth
2023-02-21 12:40 ` Dov Murik
2023-03-02 0:02 ` Zhi Wang
2023-03-02 1:41 ` Dionna Amalie Glaze
2023-03-02 11:27 ` Zhi Wang
2023-03-02 11:34 ` Dov Murik
2023-02-20 18:38 ` [PATCH RFC v8 55/56] x86/sev: Document KVM_SEV_SNP_{G,S}ET_CERTS Michael Roth
2023-02-20 18:38 ` [PATCH RFC v8 56/56] iommu/amd: Add IOMMU_SNP_SHUTDOWN support Michael Roth
2023-03-01 16:56 ` [PATCH RFC v8 00/56] Add AMD Secure Nested Paging (SEV-SNP) Hypervisor Support Dave Hansen
2023-03-01 22:59 ` Zhi Wang
2023-03-01 23:39 ` Dave Hansen
2023-08-03 18:27 ` Schander, Johanna 'Mimoja' Amelie
2023-08-04 1:01 ` Kalra, Ashish
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