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[v1,12/12] KVM: PPC: Book3S HV: Ensure MSR[HV] is always clear in guest MSR

Message ID 20210412014845.1517916-13-npiggin@gmail.com
State New
Headers show
Series minor KVM fixes and cleanups | expand

Commit Message

Nicholas Piggin April 12, 2021, 1:48 a.m. UTC 
Rather than clear the HV bit from the MSR at guest entry, make it clear
that the hypervisor does not allow the guest to set the bit.

The HV clear is kept in guest entry for now, but a future patch will
warn if it is set.

Acked-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/book3s_hv_builtin.c | 4 ++--
 arch/powerpc/kvm/book3s_hv_nested.c  | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

Comments

Fabiano Rosas April 16, 2021, 6:34 p.m. UTC | #1 
Nicholas Piggin <npiggin@gmail.com> writes:

> Rather than clear the HV bit from the MSR at guest entry, make it clear
> that the hypervisor does not allow the guest to set the bit.
>
> The HV clear is kept in guest entry for now, but a future patch will
> warn if it is set.
>
> Acked-by: Paul Mackerras <paulus@ozlabs.org>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>

> ---
>  arch/powerpc/kvm/book3s_hv_builtin.c | 4 ++--
>  arch/powerpc/kvm/book3s_hv_nested.c  | 4 ++--
>  2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
> index 41cb03d0bde4..7a0e33a9c980 100644
> --- a/arch/powerpc/kvm/book3s_hv_builtin.c
> +++ b/arch/powerpc/kvm/book3s_hv_builtin.c
> @@ -662,8 +662,8 @@ static void kvmppc_end_cede(struct kvm_vcpu *vcpu)
>
>  void kvmppc_set_msr_hv(struct kvm_vcpu *vcpu, u64 msr)
>  {
> -	/* Guest must always run with ME enabled. */
> -	msr = msr | MSR_ME;
> +	/* Guest must always run with ME enabled, HV disabled. */
> +	msr = (msr | MSR_ME) & ~MSR_HV;
>
>  	/*
>  	 * Check for illegal transactional state bit combination
> diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
> index fb03085c902b..60724f674421 100644
> --- a/arch/powerpc/kvm/book3s_hv_nested.c
> +++ b/arch/powerpc/kvm/book3s_hv_nested.c
> @@ -344,8 +344,8 @@ long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
>  	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
>  	vcpu->arch.regs = l2_regs;
>
> -	/* Guest must always run with ME enabled. */
> -	vcpu->arch.shregs.msr = vcpu->arch.regs.msr | MSR_ME;
> +	/* Guest must always run with ME enabled, HV disabled. */
> +	vcpu->arch.shregs.msr = (vcpu->arch.regs.msr | MSR_ME) & ~MSR_HV;
>
>  	sanitise_hv_regs(vcpu, &l2_hv);
>  	restore_hv_regs(vcpu, &l2_hv);
diff mbox series

Patch

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 41cb03d0bde4..7a0e33a9c980 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -662,8 +662,8 @@  static void kvmppc_end_cede(struct kvm_vcpu *vcpu)
 
 void kvmppc_set_msr_hv(struct kvm_vcpu *vcpu, u64 msr)
 {
-	/* Guest must always run with ME enabled. */
-	msr = msr | MSR_ME;
+	/* Guest must always run with ME enabled, HV disabled. */
+	msr = (msr | MSR_ME) & ~MSR_HV;
 
 	/*
 	 * Check for illegal transactional state bit combination
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index fb03085c902b..60724f674421 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -344,8 +344,8 @@  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
 	vcpu->arch.regs = l2_regs;
 
-	/* Guest must always run with ME enabled. */
-	vcpu->arch.shregs.msr = vcpu->arch.regs.msr | MSR_ME;
+	/* Guest must always run with ME enabled, HV disabled. */
+	vcpu->arch.shregs.msr = (vcpu->arch.regs.msr | MSR_ME) & ~MSR_HV;
 
 	sanitise_hv_regs(vcpu, &l2_hv);
 	restore_hv_regs(vcpu, &l2_hv);