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Subject[PATCH RFC v1 3/9] KVM: x86/mmu: Add hook to pin PFNs on demand in MMU
Date
Use vendor code via kvm_x86_ops hooks for pinning.

Signed-off-by: Nikunj A Dadhania <nikunj@amd.com>
---
arch/x86/include/asm/kvm-x86-ops.h | 1 +
arch/x86/include/asm/kvm_host.h | 3 +++
arch/x86/kvm/mmu/mmu.c | 15 +++++++++++++++
3 files changed, 19 insertions(+)

diff --git a/arch/x86/include/asm/kvm-x86-ops.h b/arch/x86/include/asm/kvm-x86-ops.h
index d39e0de06be2..8efb43d92eef 100644
--- a/arch/x86/include/asm/kvm-x86-ops.h
+++ b/arch/x86/include/asm/kvm-x86-ops.h
@@ -88,6 +88,7 @@ KVM_X86_OP(set_tss_addr)
KVM_X86_OP(set_identity_map_addr)
KVM_X86_OP(get_mt_mask)
KVM_X86_OP(load_mmu_pgd)
+KVM_X86_OP(pin_pfn)
KVM_X86_OP_NULL(has_wbinvd_exit)
KVM_X86_OP(get_l2_tsc_offset)
KVM_X86_OP(get_l2_tsc_multiplier)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index ec9830d2aabf..df11f1fb76de 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1418,6 +1418,9 @@ struct kvm_x86_ops {

void (*load_mmu_pgd)(struct kvm_vcpu *vcpu, hpa_t root_hpa,
int root_level);
+ bool (*pin_pfn)(struct kvm_vcpu *vcpu, struct kvm_memory_slot *slot,
+ kvm_pfn_t pfn, hva_t hva, bool write,
+ enum pg_level level);

bool (*has_wbinvd_exit)(void);

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index db1feecd6fed..b94e5e71653e 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4001,6 +4001,16 @@ static bool is_page_fault_stale(struct kvm_vcpu *vcpu,
mmu_notifier_retry_hva(vcpu->kvm, mmu_seq, fault->hva);
}

+static bool kvm_pin_pfn(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
+{
+ if (is_error_noslot_pfn(fault->pfn) || kvm_is_reserved_pfn(fault->pfn) ||
+ !kvm_x86_ops.pin_pfn)
+ return true;
+
+ return kvm_x86_ops.pin_pfn(vcpu, fault->slot, fault->pfn, fault->hva,
+ fault->write, fault->goal_level);
+}
+
static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
{
bool is_tdp_mmu_fault = is_tdp_mmu(vcpu->arch.mmu);
@@ -4035,6 +4045,9 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault

kvm_mmu_hugepage_adjust(vcpu, fault);

+ if (memslot_is_encrypted(fault->slot) && !kvm_pin_pfn(vcpu, fault))
+ goto out_release;
+
if (is_tdp_mmu_fault)
read_lock(&vcpu->kvm->mmu_lock);
else
@@ -4057,6 +4070,8 @@ static int direct_page_fault(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault
read_unlock(&vcpu->kvm->mmu_lock);
else
write_unlock(&vcpu->kvm->mmu_lock);
+
+out_release:
kvm_release_pfn_clean(fault->pfn);
return r;
}
--
2.32.0
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