diff mbox series

[v4,10/46] KVM: PPC: Book3S HV: Ensure MSR[ME] is always set in guest MSR

Message ID 20210323010305.1045293-11-npiggin@gmail.com
State New
Headers show
Series KVM: PPC: Book3S: C-ify the P9 entry/exit code | expand

Commit Message

Nicholas Piggin March 23, 2021, 1:02 a.m. UTC 
Rather than add the ME bit to the MSR at guest entry, make it clear
that the hypervisor does not allow the guest to clear the bit.

The ME set is kept in guest entry for now, but a future patch will
warn if it's not present.

Reviewed-by: Daniel Axtens <dja@axtens.net>
Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/kvm/book3s_hv_builtin.c | 3 +++
 arch/powerpc/kvm/book3s_hv_nested.c  | 4 +++-
 2 files changed, 6 insertions(+), 1 deletion(-)

Comments

Paul Mackerras March 31, 2021, 4:56 a.m. UTC | #1 
On Tue, Mar 23, 2021 at 11:02:29AM +1000, Nicholas Piggin wrote:
> Rather than add the ME bit to the MSR at guest entry, make it clear
> that the hypervisor does not allow the guest to clear the bit.
> 
> The ME set is kept in guest entry for now, but a future patch will
> warn if it's not present.
> 
> Reviewed-by: Daniel Axtens <dja@axtens.net>
> Reviewed-by: Fabiano Rosas <farosas@linux.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Acked-by: Paul Mackerras <paulus@ozlabs.org>
diff mbox series

Patch

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 158d309b42a3..41cb03d0bde4 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -662,6 +662,9 @@  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;
+
 	/*
 	 * Check for illegal transactional state bit combination
 	 * and if we find it, force the TS field to a safe state.
diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 851e3f527eb2..886c7fa86add 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -328,7 +328,9 @@  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	vcpu->arch.nested = l2;
 	vcpu->arch.nested_vcpu_id = l2_hv.vcpu_token;
 	vcpu->arch.regs = l2_regs;
-	vcpu->arch.shregs.msr = vcpu->arch.regs.msr;
+
+	/* Guest must always run with ME enabled. */
+	vcpu->arch.shregs.msr = vcpu->arch.regs.msr | MSR_ME;
 
 	sanitise_hv_regs(vcpu, &l2_hv);
 	restore_hv_regs(vcpu, &l2_hv);