Thread (23 messages) 23 messages, 3 authors, 2023-12-21

Re: [PATCH 01/12] KVM: PPC: Book3S HV nestedv2: Invalidate RPT before deleting a guest

From: Aneesh Kumar K.V (IBM) <aneesh.kumar@kernel.org>
Date: 2023-12-07 09:16:21
Also in: kvm

Vaibhav Jain [off-list ref] writes:
quoted hunk ↗ jump to hunk
From: Jordan Niethe <redacted>

An L0 must invalidate the L2's RPT during H_GUEST_DELETE if this has not
already been done. This is a slow operation that means H_GUEST_DELETE
must return H_BUSY multiple times before completing. Invalidating the
tables before deleting the guest so there is less work for the L0 to do.

Signed-off-by: Jordan Niethe <redacted>
---
 arch/powerpc/include/asm/kvm_book3s.h | 1 +
 arch/powerpc/kvm/book3s_hv.c          | 6 ++++--
 arch/powerpc/kvm/book3s_hv_nested.c   | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h
index 4f527d09c92b..a37736ed3728 100644
--- a/arch/powerpc/include/asm/kvm_book3s.h
+++ b/arch/powerpc/include/asm/kvm_book3s.h
@@ -302,6 +302,7 @@ void kvmhv_nested_exit(void);
 void kvmhv_vm_nested_init(struct kvm *kvm);
 long kvmhv_set_partition_table(struct kvm_vcpu *vcpu);
 long kvmhv_copy_tofrom_guest_nested(struct kvm_vcpu *vcpu);
+void kvmhv_flush_lpid(u64 lpid);
 void kvmhv_set_ptbl_entry(u64 lpid, u64 dw0, u64 dw1);
 void kvmhv_release_all_nested(struct kvm *kvm);
 long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu);
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1ed6ec140701..5543e8490cd9 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -5691,10 +5691,12 @@ static void kvmppc_core_destroy_vm_hv(struct kvm *kvm)
 			kvmhv_set_ptbl_entry(kvm->arch.lpid, 0, 0);
 	}
 
-	if (kvmhv_is_nestedv2())
+	if (kvmhv_is_nestedv2()) {
+		kvmhv_flush_lpid(kvm->arch.lpid);
 		plpar_guest_delete(0, kvm->arch.lpid);
I am not sure I follow the optimization here. I would expect the
hypervisor to kill all the translation caches as part of guest_delete.
What is the benefit of doing a lpid flush outside the guest delete?
quoted hunk ↗ jump to hunk
-	else
+	} else {
 		kvmppc_free_lpid(kvm->arch.lpid);
+	}
 
 	kvmppc_free_pimap(kvm);
 }
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 3b658b8696bc..5c375ec1a3c6 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -503,7 +503,7 @@ void kvmhv_nested_exit(void)
 	}
 }
 
-static void kvmhv_flush_lpid(u64 lpid)
+void kvmhv_flush_lpid(u64 lpid)
 {
 	long rc;
 
-- 
2.42.0
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