diff mbox series

[v4,2/2] KVM: PPC: Book3S HV: Stop forwarding all HFUs to L1

Message ID 20210722221240.2384655-3-farosas@linux.ibm.com (mailing list archive)
State Superseded
Headers show
Series KVM: PPC: Book3S HV: Nested guest state sanitising changes | expand
Related show

Commit Message

Fabiano Rosas July 22, 2021, 10:12 p.m. UTC 
If the nested hypervisor has no access to a facility because it has
been disabled by the host, it should also not be able to see the
Hypervisor Facility Unavailable that arises from one of its guests
trying to access the facility.

This patch turns a HFU that happened in L2 into a Hypervisor Emulation
Assistance interrupt and forwards it to L1 for handling. The ones that
happened because L1 explicitly disabled the facility for L2 are still
let through, along with the corresponding Cause bits in the HFSCR.

Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
---
 arch/powerpc/kvm/book3s_hv_nested.c | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)
diff mbox series

Patch

diff --git a/arch/powerpc/kvm/book3s_hv_nested.c b/arch/powerpc/kvm/book3s_hv_nested.c
index 3804dc50ebe8..d171a400e4d5 100644
--- a/arch/powerpc/kvm/book3s_hv_nested.c
+++ b/arch/powerpc/kvm/book3s_hv_nested.c
@@ -99,7 +99,7 @@  static void byteswap_hv_regs(struct hv_guest_state *hr)
 	hr->dawrx1 = swab64(hr->dawrx1);
 }
 
-static void save_hv_return_state(struct kvm_vcpu *vcpu, int trap,
+static void save_hv_return_state(struct kvm_vcpu *vcpu,
 				 struct hv_guest_state *hr)
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;
@@ -128,7 +128,7 @@  static void save_hv_return_state(struct kvm_vcpu *vcpu, int trap,
 	hr->pidr = vcpu->arch.pid;
 	hr->cfar = vcpu->arch.cfar;
 	hr->ppr = vcpu->arch.ppr;
-	switch (trap) {
+	switch (vcpu->arch.trap) {
 	case BOOK3S_INTERRUPT_H_DATA_STORAGE:
 		hr->hdar = vcpu->arch.fault_dar;
 		hr->hdsisr = vcpu->arch.fault_dsisr;
@@ -137,6 +137,27 @@  static void save_hv_return_state(struct kvm_vcpu *vcpu, int trap,
 	case BOOK3S_INTERRUPT_H_INST_STORAGE:
 		hr->asdr = vcpu->arch.fault_gpa;
 		break;
+	case BOOK3S_INTERRUPT_H_FAC_UNAVAIL:
+	{
+		u8 cause = vcpu->arch.hfscr >> 56;
+
+		WARN_ON_ONCE(cause >= BITS_PER_LONG);
+
+		if (!(hr->hfscr & (1UL << cause)))
+			break;
+
+		/*
+		 * We have disabled this facility, so it does not
+		 * exist from L1's perspective. Turn it into a HEAI.
+		 */
+		vcpu->arch.trap = BOOK3S_INTERRUPT_H_EMUL_ASSIST;
+		kvmppc_load_last_inst(vcpu, INST_GENERIC, &vcpu->arch.emul_inst);
+
+		/* Don't leak the cause field */
+		hr->hfscr &= ~HFSCR_INTR_CAUSE;
+
+		fallthrough;
+	}
 	case BOOK3S_INTERRUPT_H_EMUL_ASSIST:
 		hr->heir = vcpu->arch.emul_inst;
 		break;
@@ -374,7 +395,7 @@  long kvmhv_enter_nested_guest(struct kvm_vcpu *vcpu)
 	delta_spurr = vcpu->arch.spurr - l2_hv.spurr;
 	delta_ic = vcpu->arch.ic - l2_hv.ic;
 	delta_vtb = vc->vtb - l2_hv.vtb;
-	save_hv_return_state(vcpu, vcpu->arch.trap, &l2_hv);
+	save_hv_return_state(vcpu, &l2_hv);
 
 	/* restore L1 state */
 	vcpu->arch.nested = NULL;