41afd2473d
[ Upstream commit e5c972c1fadacc858b6a564d056f177275238040 ]
The Hyper-V "EnlightenedNptTlb" enlightenment is always enabled when KVM
is running on top of Hyper-V and Hyper-V exposes support for it (which
is always). On AMD CPUs this enlightenment results in ASID invalidations
not flushing TLB entries derived from the NPT. To force the underlying
(L0) hypervisor to rebuild its shadow page tables, an explicit hypercall
is needed.
The original KVM implementation of Hyper-V's "EnlightenedNptTlb" on SVM
only added remote TLB flush hooks. This worked out fine for a while, as
sufficient remote TLB flushes where being issued in KVM to mask the
problem. Since v5.17, changes in the TDP code reduced the number of
flushes and the out-of-sync TLB prevents guests from booting
successfully.
Split svm_flush_tlb_current() into separate callbacks for the 3 cases
(guest/all/current), and issue the required Hyper-V hypercall when a
Hyper-V TLB flush is needed. The most important case where the TLB flush
was missing is when loading a new PGD, which is followed by what is now
svm_flush_tlb_current().
Cc: stable@vger.kernel.org # v5.17+
Fixes: 1e0c7d4075 ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
Link: https://lore.kernel.org/lkml/43980946-7bbf-dcef-7e40-af904c456250@linux.microsoft.com/
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jeremi Piotrowski <jpiotrowski@linux.microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20230324145233.4585-1-jpiotrowski@linux.microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
26 lines
623 B
C
26 lines
623 B
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* KVM L1 hypervisor optimizations on Hyper-V.
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*/
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#ifndef __ARCH_X86_KVM_KVM_ONHYPERV_H__
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#define __ARCH_X86_KVM_KVM_ONHYPERV_H__
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#if IS_ENABLED(CONFIG_HYPERV)
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int hv_remote_flush_tlb_with_range(struct kvm *kvm,
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struct kvm_tlb_range *range);
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int hv_remote_flush_tlb(struct kvm *kvm);
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void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp);
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#else /* !CONFIG_HYPERV */
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static inline int hv_remote_flush_tlb(struct kvm *kvm)
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{
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return -EOPNOTSUPP;
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}
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static inline void hv_track_root_tdp(struct kvm_vcpu *vcpu, hpa_t root_tdp)
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{
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}
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#endif /* !CONFIG_HYPERV */
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#endif
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