From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: seanjc@google.com
Subject: Re: [PATCH v2 15/18] KVM: x86/mmu: rename kvm_mmu_new_pgd, introduce variant that calls get_guest_pgd
Date: Fri, 18 Feb 2022 10:39:26 +0100 [thread overview]
Message-ID: <ae3002da-e931-1e08-7a23-8cd296bf8313@redhat.com> (raw)
In-Reply-To: <20220217210340.312449-16-pbonzini@redhat.com>
On 2/17/22 22:03, Paolo Bonzini wrote:
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index adcee7c305ca..9800c8883a48 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1189,7 +1189,7 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
> return 1;
>
> if (cr3 != kvm_read_cr3(vcpu))
> - kvm_mmu_new_pgd(vcpu, cr3);
> + kvm_mmu_update_root(vcpu);
>
> vcpu->arch.cr3 = cr3;
> kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
Uh-oh, this has to become:
vcpu->arch.cr3 = cr3;
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
if (!is_pae_paging(vcpu))
kvm_mmu_update_root(vcpu);
The regression would go away after patch 16, but this is more tidy apart
from having to check is_pae_paging *again*.
Incremental patch:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index adcee7c305ca..0085e9fba372 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1188,11 +1189,11 @@ int kvm_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
if (is_pae_paging(vcpu) && !load_pdptrs(vcpu, cr3))
return 1;
- if (cr3 != kvm_read_cr3(vcpu))
- kvm_mmu_update_root(vcpu);
-
vcpu->arch.cr3 = cr3;
kvm_register_mark_dirty(vcpu, VCPU_EXREG_CR3);
+ if (!is_pae_paging(vcpu))
+ kvm_mmu_update_root(vcpu);
+
/* Do not call post_set_cr3, we do not get here for confidential guests. */
An alternative is to move the vcpu->arch.cr3 update in load_pdptrs.
Reviewers, let me know if you prefer that, then I'll send v3.
Paolo
next prev parent reply other threads:[~2022-02-18 9:39 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 21:03 [PATCH v2 00/18] KVM: MMU: do not unload MMU roots on all role changes Paolo Bonzini
2022-02-17 21:03 ` [PATCH v2 01/18] KVM: x86: host-initiated EFER.LME write affects the MMU Paolo Bonzini
2022-02-18 17:08 ` Sean Christopherson
2022-02-18 17:26 ` Paolo Bonzini
2022-02-23 13:40 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 02/18] KVM: x86: do not deliver asynchronous page faults if CR0.PG=0 Paolo Bonzini
2022-02-18 17:12 ` Sean Christopherson
2022-02-23 14:07 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 03/18] KVM: x86/mmu: WARN if PAE roots linger after kvm_mmu_unload Paolo Bonzini
2022-02-18 17:14 ` Sean Christopherson
2022-02-18 17:23 ` Paolo Bonzini
2022-02-23 14:11 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 04/18] KVM: x86/mmu: avoid NULL-pointer dereference on page freeing bugs Paolo Bonzini
2022-02-18 17:15 ` Sean Christopherson
2022-02-23 14:12 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 05/18] KVM: x86/mmu: use struct kvm_mmu_root_info for mmu->root Paolo Bonzini
2022-02-23 14:39 ` Maxim Levitsky
2022-02-23 15:42 ` Sean Christopherson
2022-02-17 21:03 ` [PATCH v2 06/18] KVM: x86/mmu: do not consult levels when freeing roots Paolo Bonzini
2022-02-18 17:27 ` Sean Christopherson
2022-02-23 14:59 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 07/18] KVM: x86/mmu: Do not use guest root level in audit Paolo Bonzini
2022-02-18 18:37 ` Sean Christopherson
2022-02-18 18:46 ` Paolo Bonzini
2022-02-23 15:02 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 08/18] KVM: x86/mmu: do not pass vcpu to root freeing functions Paolo Bonzini
2022-02-18 18:39 ` Sean Christopherson
2022-02-23 15:16 ` Maxim Levitsky
2022-02-23 15:48 ` Sean Christopherson
2022-02-17 21:03 ` [PATCH v2 09/18] KVM: x86/mmu: look for a cached PGD when going from 32-bit to 64-bit Paolo Bonzini
2022-02-18 18:08 ` Sean Christopherson
2022-02-23 16:01 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 10/18] KVM: x86/mmu: load new PGD after the shadow MMU is initialized Paolo Bonzini
2022-02-18 23:59 ` Sean Christopherson
2022-02-23 16:20 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 11/18] KVM: x86/mmu: Always use current mmu's role when loading new PGD Paolo Bonzini
2022-02-18 23:59 ` Sean Christopherson
2022-02-23 16:23 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 12/18] KVM: x86/mmu: clear MMIO cache when unloading the MMU Paolo Bonzini
2022-02-18 23:59 ` Sean Christopherson
2022-02-23 16:32 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 13/18] KVM: x86: reset and reinitialize the MMU in __set_sregs_common Paolo Bonzini
2022-02-19 0:22 ` Sean Christopherson
2022-02-23 16:48 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 14/18] KVM: x86/mmu: avoid indirect call for get_cr3 Paolo Bonzini
2022-02-18 20:30 ` Sean Christopherson
2022-02-19 10:03 ` Paolo Bonzini
2022-02-24 11:02 ` Maxim Levitsky
2022-02-24 15:12 ` Sean Christopherson
2022-02-24 15:14 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 15/18] KVM: x86/mmu: rename kvm_mmu_new_pgd, introduce variant that calls get_guest_pgd Paolo Bonzini
2022-02-18 9:39 ` Paolo Bonzini [this message]
2022-02-18 21:00 ` Sean Christopherson
2022-02-24 15:41 ` Maxim Levitsky
2022-02-25 17:40 ` Sean Christopherson
2022-02-17 21:03 ` [PATCH v2 16/18] KVM: x86: introduce KVM_REQ_MMU_UPDATE_ROOT Paolo Bonzini
2022-02-18 21:45 ` Sean Christopherson
2022-02-19 7:54 ` Paolo Bonzini
2022-02-22 16:06 ` Sean Christopherson
2022-02-24 15:50 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 17/18] KVM: x86: flush TLB separately from MMU reset Paolo Bonzini
2022-02-18 23:57 ` Sean Christopherson
2022-02-21 15:01 ` Paolo Bonzini
2022-02-24 16:11 ` Maxim Levitsky
2022-02-17 21:03 ` [PATCH v2 18/18] KVM: x86: do not unload MMU roots on all role changes Paolo Bonzini
2022-02-24 16:25 ` Maxim Levitsky
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