* [RFC 01/19] KVM: x86/mmu: Fix TLB flush range when handling disconnected pt
[not found] <20211110223010.1392399-1-bgardon@google.com>
@ 2021-11-10 22:29 ` Ben Gardon
2021-11-11 17:44 ` David Matlack
0 siblings, 1 reply; 2+ messages in thread
From: Ben Gardon @ 2021-11-10 22:29 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Paolo Bonzini, Peter Xu, Sean Christopherson, Peter Shier,
David Matlack, Mingwei Zhang, Yulei Zhang, Wanpeng Li,
Xiao Guangrong, Kai Huang, Keqian Zhu, David Hildenbrand,
Ben Gardon, stable
When recursively clearing out disconnected pts, the range based TLB
flush in handle_removed_tdp_mmu_page uses the wrong starting GFN,
resulting in the flush mostly missing the affected range. Fix this by
using base_gfn for the flush.
Fixes: a066e61f13cf ("KVM: x86/mmu: Factor out handling of removed page tables")
CC: stable@vger.kernel.org
Signed-off-by: Ben Gardon <bgardon@google.com>
---
arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 7c5dd83e52de..866c2b191e1e 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -374,7 +374,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
shared);
}
- kvm_flush_remote_tlbs_with_address(kvm, gfn,
+ kvm_flush_remote_tlbs_with_address(kvm, base_gfn,
KVM_PAGES_PER_HPAGE(level + 1));
call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);
--
2.34.0.rc0.344.g81b53c2807-goog
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [RFC 01/19] KVM: x86/mmu: Fix TLB flush range when handling disconnected pt
2021-11-10 22:29 ` [RFC 01/19] KVM: x86/mmu: Fix TLB flush range when handling disconnected pt Ben Gardon
@ 2021-11-11 17:44 ` David Matlack
0 siblings, 0 replies; 2+ messages in thread
From: David Matlack @ 2021-11-11 17:44 UTC (permalink / raw)
To: Ben Gardon
Cc: linux-kernel, kvm, Paolo Bonzini, Peter Xu, Sean Christopherson,
Peter Shier, Mingwei Zhang, Yulei Zhang, Wanpeng Li,
Xiao Guangrong, Kai Huang, Keqian Zhu, David Hildenbrand, stable
On Wed, Nov 10, 2021 at 02:29:52PM -0800, Ben Gardon wrote:
> When recursively clearing out disconnected pts, the range based TLB
> flush in handle_removed_tdp_mmu_page uses the wrong starting GFN,
> resulting in the flush mostly missing the affected range. Fix this by
> using base_gfn for the flush.
>
> Fixes: a066e61f13cf ("KVM: x86/mmu: Factor out handling of removed page tables")
> CC: stable@vger.kernel.org
>
> Signed-off-by: Ben Gardon <bgardon@google.com>
> ---
> arch/x86/kvm/mmu/tdp_mmu.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
> index 7c5dd83e52de..866c2b191e1e 100644
> --- a/arch/x86/kvm/mmu/tdp_mmu.c
> +++ b/arch/x86/kvm/mmu/tdp_mmu.c
> @@ -374,7 +374,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
> shared);
> }
>
> - kvm_flush_remote_tlbs_with_address(kvm, gfn,
> + kvm_flush_remote_tlbs_with_address(kvm, base_gfn,
Suggest pulling the definition of gfn into the for loop as well (along
with sptep and old_child_spte for that matter) so that referencing it
here isn't even possible.
> KVM_PAGES_PER_HPAGE(level + 1));
>
> call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);
> --
> 2.34.0.rc0.344.g81b53c2807-goog
>
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2021-11-10 22:29 ` [RFC 01/19] KVM: x86/mmu: Fix TLB flush range when handling disconnected pt Ben Gardon
2021-11-11 17:44 ` David Matlack
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