linux-kernel - [RFC PATCH v2 06/31] KVM: arm64: Invalidate virtual EL2 TLB entries when needed

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Date:   Mon,  2 Oct 2017 22:10:48 -0500
From:   Jintack Lim <jintack.lim@...aro.org>
To:     christoffer.dall@...aro.org, marc.zyngier@....com,
        kvmarm@...ts.cs.columbia.edu
Cc:     jintack@...columbia.edu, pbonzini@...hat.com, rkrcmar@...hat.com,
        catalin.marinas@....com, will.deacon@....com,
        linux@...linux.org.uk, mark.rutland@....com,
        linux-arm-kernel@...ts.infradead.org, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Jintack Lim <jintack.lim@...aro.org>
Subject: [RFC PATCH v2 06/31] KVM: arm64: Invalidate virtual EL2 TLB entries when needed

From: Christoffer Dall <christoffer.dall@...aro.org>

Sometimes when we are invalidating the TLB for a certain S2 MMU
context, this context can also have EL2 context associated with it and
we have to invalidate this too.

Signed-off-by: Christoffer Dall <christoffer.dall@...aro.org>
Signed-off-by: Jintack Lim <jintack.lim@...aro.org>
---
 virt/kvm/arm/arm.c |  5 +++++
 virt/kvm/arm/mmu.c | 23 ++++++++++++++++++++++-
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
index 41e0654..63dd897 100644
--- a/virt/kvm/arm/arm.c
+++ b/virt/kvm/arm/arm.c
@@ -362,6 +362,11 @@ void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 		u64 vttbr = kvm_get_vttbr(&mmu->vmid, mmu);
 
 		kvm_call_hyp(__kvm_tlb_flush_local_vmid, vttbr);
+
+		if (mmu->el2_vmid.vmid) {
+			vttbr = kvm_get_vttbr(&mmu->el2_vmid, mmu);
+			kvm_call_hyp(__kvm_tlb_flush_local_vmid, vttbr);
+		}
 		*last_ran = vcpu->vcpu_id;
 	}
 
diff --git a/virt/kvm/arm/mmu.c b/virt/kvm/arm/mmu.c
index 0edcf23..184cdc9 100644
--- a/virt/kvm/arm/mmu.c
+++ b/virt/kvm/arm/mmu.c
@@ -64,7 +64,21 @@ void kvm_flush_remote_tlbs(struct kvm *kvm)
 	struct kvm_s2_mmu *mmu = &kvm->arch.mmu;
 	u64 vttbr = kvm_get_vttbr(&mmu->vmid, mmu);
 
-	kvm_call_hyp(__kvm_tlb_flush_vmid, vttbr);
+	if (!mmu->el2_vmid.vmid) {
+		/*
+		 * For a normal (i.e. non-nested) guest, flush entries for the
+		 * given VMID *
+		 */
+		kvm_call_hyp(__kvm_tlb_flush_vmid, vttbr);
+	} else {
+		/*
+		 * When supporting nested virtualization, we can have multiple
+		 * VMIDs in play for each VCPU in the VM, so it's really not
+		 * worth it to try to quiesce the system and flush all the
+		 * VMIDs that may be in use, instead just nuke the whole thing.
+		 */
+		kvm_call_hyp(__kvm_flush_vm_context);
+	}
 }
 
 static void kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa)
@@ -72,6 +86,13 @@ static void kvm_tlb_flush_vmid_ipa(struct kvm_s2_mmu *mmu, phys_addr_t ipa)
 	u64 vttbr = kvm_get_vttbr(&mmu->vmid, mmu);
 
 	kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, vttbr, ipa);
+
+	if (!mmu->el2_vmid.vmid) {
+		/* Nothing to do more for a non-nested guest */
+		return;
+	}
+	vttbr = kvm_get_vttbr(&mmu->el2_vmid, mmu);
+	kvm_call_hyp(__kvm_tlb_flush_vmid_ipa, vttbr, ipa);
 }
 
 /*
-- 
1.9.1