From: Paolo Bonzini <pbonzini@redhat.com>
To: David Woodhouse <dwmw2@infradead.org>,
Sean Christopherson <seanjc@google.com>
Cc: kvm <kvm@vger.kernel.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Joao Martins <joao.m.martins@oracle.com>,
"jmattson@google.com" <jmattson@google.com>,
"wanpengli@tencent.com" <wanpengli@tencent.com>,
"vkuznets@redhat.com" <vkuznets@redhat.com>,
"mtosatti@redhat.com" <mtosatti@redhat.com>,
"joro@8bytes.org" <joro@8bytes.org>,
karahmed@amazon.com
Subject: Re: [RFC PATCH 0/11] Rework gfn_to_pfn_cache
Date: Tue, 16 Nov 2021 15:57:38 +0100 [thread overview]
Message-ID: <ad0648ac-b72a-1692-c608-b37109b3d250@redhat.com> (raw)
In-Reply-To: <19bf769ef623e0392016975b12133d9a3be210b3.camel@infradead.org>
On 11/16/21 15:25, David Woodhouse wrote:
> + /*
> + * If the guest requires direct access to mapped L1 pages, check
> + * the caches are valid. Will raise KVM_REQ_GET_NESTED_STATE_PAGES
> + * to go and revalidate them, if necessary.
> + */
> + if (is_guest_mode(vcpu) && kvm_x86_ops.nested_ops->check_guest_maps)
> + kvm_x86_ops.nested_ops->check_guest_maps();
> +
This should not be needed, should it? As long as the gfn-to-pfn
cache's vcpu field is handled properly, the request will just cause
the vCPU not to enter. It would have to take the gpc->lock around
changes to gpc->vcpu though (meaning: it's probably best to add a
function gfn_to_pfn_cache_set_vcpu).
Doing it lockless would be harder; I cannot think of any well-known
pattern that is good for this scenario.
> That check_guest_maps() function can validate the caches which the L2
> guest is actually using in the VMCS02, and if they need to be refreshed
> then raising a req will immediately break out of vcpu_enter_guest() to
> allow that to happen.
>
> I*think* we can just use KVM_REQ_GET_NESTED_STATE_PAGES for that and
> don't need to invent a new one?
Yes, maybe even do it unconditionally?
- if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu)) {
+ if (kvm_check_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu) ||
kvm_check_request(KVM_REQ_GPC_INVALIDATE, vcpu))
if the gfn-to-pfn cache's vcpu field is set/reset properly across nested
VM entry and exit.
Paolo
next prev parent reply other threads:[~2021-11-16 14:58 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-01 14:09 [PATCH] KVM: x86: Fix recording of guest steal time / preempted status David Woodhouse
2021-11-02 16:38 ` [PATCH v2] " David Woodhouse
2021-11-02 17:01 ` Paolo Bonzini
2021-11-02 17:11 ` David Woodhouse
2021-11-02 17:19 ` Paolo Bonzini
2021-11-02 17:26 ` David Woodhouse
2021-11-02 17:36 ` [PATCH v3] " David Woodhouse
2021-11-11 13:23 ` Paolo Bonzini
2021-11-12 8:28 ` David Woodhouse
2021-11-12 9:31 ` Paolo Bonzini
2021-11-12 9:54 ` David Woodhouse
2021-11-12 10:49 ` Paolo Bonzini
2021-11-12 11:29 ` David Woodhouse
2021-11-12 12:27 ` Paolo Bonzini
2021-11-12 13:28 ` David Woodhouse
2021-11-12 14:56 ` Paolo Bonzini
2021-11-12 15:27 ` David Woodhouse
2021-11-15 16:47 ` [RFC PATCH 0/11] Rework gfn_to_pfn_cache David Woodhouse
2021-11-15 16:50 ` [PATCH 01/11] KVM: x86: Fix steal time asm constraints in 32-bit mode David Woodhouse
2021-11-15 16:50 ` [PATCH 02/11] KVM: x86/xen: Fix get_attr of KVM_XEN_ATTR_TYPE_SHARED_INFO David Woodhouse
2021-11-15 16:50 ` [PATCH 03/11] KVM: selftests: Add event channel upcall support to xen_shinfo_test David Woodhouse
2021-11-15 16:50 ` [PATCH 04/11] KVM: x86/xen: Use sizeof_field() instead of open-coding it David Woodhouse
2021-11-15 16:50 ` [PATCH 05/11] KVM: nVMX: Use kvm_{read,write}_guest_cached() for shadow_vmcs12 David Woodhouse
2021-11-15 16:50 ` [PATCH 06/11] KVM: nVMX: Use kvm_read_guest_offset_cached() for nested VMCS check David Woodhouse
2021-11-15 16:50 ` [PATCH 07/11] KVM: nVMX: Use a gfn_to_hva_cache for vmptrld David Woodhouse
2021-11-15 16:50 ` [PATCH 08/11] KVM: Kill kvm_map_gfn() / kvm_unmap_gfn() and gfn_to_pfn_cache David Woodhouse
2021-11-16 10:21 ` Paolo Bonzini
2021-11-17 17:18 ` David Woodhouse
2021-11-15 16:50 ` [PATCH 09/11] KVM: Reinstate gfn_to_pfn_cache with invalidation support David Woodhouse
2021-11-15 16:50 ` [PATCH 10/11] KVM: x86/xen: Maintain valid mapping of Xen shared_info page David Woodhouse
2021-11-15 16:50 ` [PATCH 11/11] KVM: x86/xen: Add KVM_IRQ_ROUTING_XEN_EVTCHN and event channel delivery David Woodhouse
2021-11-15 17:02 ` David Woodhouse
2021-11-15 18:49 ` Paolo Bonzini
2021-11-15 18:55 ` David Woodhouse
2021-11-15 18:50 ` [RFC PATCH 0/11] Rework gfn_to_pfn_cache Paolo Bonzini
2021-11-15 19:11 ` David Woodhouse
2021-11-15 19:26 ` Paolo Bonzini
2021-11-15 22:59 ` Sean Christopherson
2021-11-15 23:22 ` David Woodhouse
2021-11-16 13:17 ` David Woodhouse
2021-11-16 14:11 ` Paolo Bonzini
2021-11-16 14:25 ` David Woodhouse
2021-11-16 14:57 ` Paolo Bonzini [this message]
2021-11-16 15:09 ` David Woodhouse
2021-11-16 15:49 ` Paolo Bonzini
2021-11-16 16:06 ` David Woodhouse
2021-11-16 17:42 ` Paolo Bonzini
2021-11-16 17:57 ` David Woodhouse
2021-11-16 18:46 ` Paolo Bonzini
2021-11-16 19:34 ` David Woodhouse
2021-11-15 23:24 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 0/7] KVM: Add Makefile.kvm for common files David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 1/7] KVM: Introduce CONFIG_HAVE_KVM_DIRTY_RING David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 2/7] KVM: Add Makefile.kvm for common files, use it for x86 David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 3/7] KVM: s390: Use Makefile.kvm for common files David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-17 7:29 ` Christian Borntraeger
2021-11-17 7:29 ` Christian Borntraeger
2021-11-17 7:29 ` Christian Borntraeger
2021-11-17 7:29 ` Christian Borntraeger
2021-11-16 11:50 ` [PATCH 4/7] KVM: mips: " David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 5/7] KVM: RISC-V: " David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 6/7] KVM: powerpc: " David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 18:43 ` Sean Christopherson
2021-11-16 18:43 ` Sean Christopherson
2021-11-16 18:43 ` Sean Christopherson
2021-11-16 18:43 ` Sean Christopherson
2021-11-16 19:13 ` David Woodhouse
2021-11-16 19:13 ` David Woodhouse
2021-11-16 19:13 ` David Woodhouse
2021-11-16 19:13 ` David Woodhouse
2021-11-16 11:50 ` [PATCH 7/7] KVM: arm64: " David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-16 11:50 ` David Woodhouse
2021-11-15 21:38 ` [RFC PATCH 0/11] Rework gfn_to_pfn_cache David Woodhouse
2021-11-12 19:44 ` [PATCH v3] KVM: x86: Fix recording of guest steal time / preempted status David Woodhouse
2021-11-03 9:47 ` [PATCH v2] " David Woodhouse
2021-11-03 12:35 ` Paolo Bonzini
2021-11-03 12:56 ` David Woodhouse
2021-11-03 13:05 ` Paolo Bonzini
2021-11-03 13:23 ` David Woodhouse
2021-11-03 13:34 ` David Woodhouse
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