KVM: PPC: Book3S: Allow XICS emulation to work in nested hosts using XIVE

Currently, the KVM code assumes that if the host kernel is using the
XIVE interrupt controller (the new interrupt controller that first
appeared in POWER9 systems), then the in-kernel XICS emulation will
use the XIVE hardware to deliver interrupts to the guest.  However,
this only works when the host is running in hypervisor mode and has
full access to all of the XIVE functionality.  It doesn't work in any
nested virtualization scenario, either with PR KVM or nested-HV KVM,
because the XICS-on-XIVE code calls directly into the native-XIVE
routines, which are not initialized and cannot function correctly
because they use OPAL calls, and OPAL is not available in a guest.

This means that using the in-kernel XICS emulation in a nested
hypervisor that is using XIVE as its interrupt controller will cause a
(nested) host kernel crash.  To fix this, we change most of the places
where the current code calls xive_enabled() to select between the
XICS-on-XIVE emulation and the plain XICS emulation to call a new
function, xics_on_xive(), which returns false in a guest.

However, there is a further twist.  The plain XICS emulation has some
functions which are used in real mode and access the underlying XICS
controller (the interrupt controller of the host) directly.  In the
case of a nested hypervisor, this means doing XICS hypercalls
directly.  When the nested host is using XIVE as its interrupt
controller, these hypercalls will fail.  Therefore this also adds
checks in the places where the XICS emulation wants to access the
underlying interrupt controller directly, and if that is XIVE, makes
the code use the virtual mode fallback paths, which call generic
kernel infrastructure rather than doing direct XICS access.

Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>

diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index eb0d79f0ca45784fdbf1c8ef126cd432b8a9f551..b3bf4f61b30c66e638f6606c92198cd9c1464a3b 100644 (file)
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -36,6 +36,8 @@
 #endif
 #ifdef CONFIG_KVM_BOOK3S_64_HANDLER
 #include <asm/paca.h>
+#include <asm/xive.h>
+#include <asm/cpu_has_feature.h>
 #endif
 
 /*
@@ -616,6 +618,18 @@ static inline int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 ir
 static inline void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu) { }
 #endif /* CONFIG_KVM_XIVE */
 
+#ifdef CONFIG_PPC_POWERNV
+static inline bool xics_on_xive(void)
+{
+       return xive_enabled() && cpu_has_feature(CPU_FTR_HVMODE);
+}
+#else
+static inline bool xics_on_xive(void)
+{
+       return false;
+}
+#endif
+
 /*
  * Prototypes for functions called only from assembler code.
  * Having prototypes reduces sparse errors.

diff --git a/arch/powerpc/kvm/book3s.c b/arch/powerpc/kvm/book3s.c
index bd1a677dd9e4dacf9f25ee6b17bb23416836d4dc..601c094f15abd3f0d46a7527d9f20d0b965f92f3 100644 (file)
--- a/arch/powerpc/kvm/book3s.c
+++ b/arch/powerpc/kvm/book3s.c
@@ -635,7 +635,7 @@ int kvmppc_get_one_reg(struct kvm_vcpu *vcpu, u64 id,
                                r = -ENXIO;
                                break;
                        }
-                       if (xive_enabled())
+                       if (xics_on_xive())
                                *val = get_reg_val(id, kvmppc_xive_get_icp(vcpu));
                        else
                                *val = get_reg_val(id, kvmppc_xics_get_icp(vcpu));
@@ -708,7 +708,7 @@ int kvmppc_set_one_reg(struct kvm_vcpu *vcpu, u64 id,
                                r = -ENXIO;
                                break;
                        }
-                       if (xive_enabled())
+                       if (xics_on_xive())
                                r = kvmppc_xive_set_icp(vcpu, set_reg_val(id, *val));
                        else
                                r = kvmppc_xics_set_icp(vcpu, set_reg_val(id, *val));
@@ -984,7 +984,7 @@ int kvmppc_book3s_hcall_implemented(struct kvm *kvm, unsigned long hcall)
 int kvm_set_irq(struct kvm *kvm, int irq_source_id, u32 irq, int level,
                bool line_status)
 {
-       if (xive_enabled())
+       if (xics_on_xive())
                return kvmppc_xive_set_irq(kvm, irq_source_id, irq, level,
                                           line_status);
        else
@@ -1037,7 +1037,7 @@ static int kvmppc_book3s_init(void)
 
 #ifdef CONFIG_KVM_XICS
 #ifdef CONFIG_KVM_XIVE
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                kvmppc_xive_init_module();
                kvm_register_device_ops(&kvm_xive_ops, KVM_DEV_TYPE_XICS);
        } else
@@ -1050,7 +1050,7 @@ static int kvmppc_book3s_init(void)
 static void kvmppc_book3s_exit(void)
 {
 #ifdef CONFIG_KVM_XICS
-       if (xive_enabled())
+       if (xics_on_xive())
                kvmppc_xive_exit_module();
 #endif
 #ifdef CONFIG_KVM_BOOK3S_32_HANDLER

diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 27112b70aa7ac66d3d92b9aa884728a0e0589c09..1860c0bc1395454025ca69e07ed0b78e8c8a20ca 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -922,7 +922,7 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
        case H_IPOLL:
        case H_XIRR_X:
                if (kvmppc_xics_enabled(vcpu)) {
-                       if (xive_enabled()) {
+                       if (xics_on_xive()) {
                                ret = H_NOT_AVAILABLE;
                                return RESUME_GUEST;
                        }
@@ -1431,7 +1431,7 @@ static int kvmppc_handle_nested_exit(struct kvm_run *run, struct kvm_vcpu *vcpu)
        case BOOK3S_INTERRUPT_HV_RM_HARD:
                vcpu->arch.trap = 0;
                r = RESUME_GUEST;
-               if (!xive_enabled())
+               if (!xics_on_xive())
                        kvmppc_xics_rm_complete(vcpu, 0);
                break;
        default:
@@ -3649,7 +3649,7 @@ static void shrink_halt_poll_ns(struct kvmppc_vcore *vc)
 #ifdef CONFIG_KVM_XICS
 static inline bool xive_interrupt_pending(struct kvm_vcpu *vcpu)
 {
-       if (!xive_enabled())
+       if (!xics_on_xive())
                return false;
        return vcpu->arch.irq_pending || vcpu->arch.xive_saved_state.pipr <
                vcpu->arch.xive_saved_state.cppr;
@@ -4209,7 +4209,7 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
                                vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
                        srcu_read_unlock(&kvm->srcu, srcu_idx);
                } else if (r == RESUME_PASSTHROUGH) {
-                       if (WARN_ON(xive_enabled()))
+                       if (WARN_ON(xics_on_xive()))
                                r = H_SUCCESS;
                        else
                                r = kvmppc_xics_rm_complete(vcpu, 0);
@@ -4733,7 +4733,7 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
                 * If xive is enabled, we route 0x500 interrupts directly
                 * to the guest.
                 */
-               if (xive_enabled())
+               if (xics_on_xive())
                        lpcr |= LPCR_LPES;
        }
 
@@ -4969,7 +4969,7 @@ static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
        if (i == pimap->n_mapped)
                pimap->n_mapped++;
 
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_set_mapped(kvm, guest_gsi, desc);
        else
                kvmppc_xics_set_mapped(kvm, guest_gsi, desc->irq_data.hwirq);
@@ -5010,7 +5010,7 @@ static int kvmppc_clr_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
                return -ENODEV;
        }
 
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_clr_mapped(kvm, guest_gsi, pimap->mapped[i].desc);
        else
                kvmppc_xics_clr_mapped(kvm, guest_gsi, pimap->mapped[i].r_hwirq);
@@ -5387,7 +5387,7 @@ static int kvmppc_book3s_init_hv(void)
         * indirectly, via OPAL.
         */
 #ifdef CONFIG_SMP
-       if (!xive_enabled() && !kvmhv_on_pseries() &&
+       if (!xics_on_xive() && !kvmhv_on_pseries() &&
            !local_paca->kvm_hstate.xics_phys) {
                struct device_node *np;
 

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index a71e2fc00a4e899be931d16ae08dd6042927bdde..b0cf22477e879b74ce4c0fa771d0deabb6c54af7 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -257,7 +257,7 @@ void kvmhv_rm_send_ipi(int cpu)
        }
 
        /* We should never reach this */
-       if (WARN_ON_ONCE(xive_enabled()))
+       if (WARN_ON_ONCE(xics_on_xive()))
            return;
 
        /* Else poke the target with an IPI */
@@ -577,7 +577,7 @@ unsigned long kvmppc_rm_h_xirr(struct kvm_vcpu *vcpu)
 {
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_xirr(vcpu);
                if (unlikely(!__xive_vm_h_xirr))
@@ -592,7 +592,7 @@ unsigned long kvmppc_rm_h_xirr_x(struct kvm_vcpu *vcpu)
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
        vcpu->arch.regs.gpr[5] = get_tb();
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_xirr(vcpu);
                if (unlikely(!__xive_vm_h_xirr))
@@ -606,7 +606,7 @@ unsigned long kvmppc_rm_h_ipoll(struct kvm_vcpu *vcpu, unsigned long server)
 {
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_ipoll(vcpu, server);
                if (unlikely(!__xive_vm_h_ipoll))
@@ -621,7 +621,7 @@ int kvmppc_rm_h_ipi(struct kvm_vcpu *vcpu, unsigned long server,
 {
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_ipi(vcpu, server, mfrr);
                if (unlikely(!__xive_vm_h_ipi))
@@ -635,7 +635,7 @@ int kvmppc_rm_h_cppr(struct kvm_vcpu *vcpu, unsigned long cppr)
 {
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_cppr(vcpu, cppr);
                if (unlikely(!__xive_vm_h_cppr))
@@ -649,7 +649,7 @@ int kvmppc_rm_h_eoi(struct kvm_vcpu *vcpu, unsigned long xirr)
 {
        if (!kvmppc_xics_enabled(vcpu))
                return H_TOO_HARD;
-       if (xive_enabled()) {
+       if (xics_on_xive()) {
                if (is_rm())
                        return xive_rm_h_eoi(vcpu, xirr);
                if (unlikely(!__xive_vm_h_eoi))

diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index b3f5786b20dcf33098280cdc1af37792b6182cbd..3b9662a4207e06125d108a2cd13724dbf665632a 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -144,6 +144,13 @@ static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu,
                return;
        }
 
+       if (xive_enabled() && kvmhv_on_pseries()) {
+               /* No XICS access or hypercalls available, too hard */
+               this_icp->rm_action |= XICS_RM_KICK_VCPU;
+               this_icp->rm_kick_target = vcpu;
+               return;
+       }
+
        /*
         * Check if the core is loaded,
         * if not, find an available host core to post to wake the VCPU,

diff --git a/arch/powerpc/kvm/book3s_rtas.c b/arch/powerpc/kvm/book3s_rtas.c
index 2d3b2b1cc272b0989858bfb4e945567ddef96369..4e178c4c1ea5074d638bbbb3eaa3315f39b2bfe0 100644 (file)
--- a/arch/powerpc/kvm/book3s_rtas.c
+++ b/arch/powerpc/kvm/book3s_rtas.c
@@ -33,7 +33,7 @@ static void kvm_rtas_set_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
        server = be32_to_cpu(args->args[1]);
        priority = be32_to_cpu(args->args[2]);
 
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_set_xive(vcpu->kvm, irq, server, priority);
        else
                rc = kvmppc_xics_set_xive(vcpu->kvm, irq, server, priority);
@@ -56,7 +56,7 @@ static void kvm_rtas_get_xive(struct kvm_vcpu *vcpu, struct rtas_args *args)
        irq = be32_to_cpu(args->args[0]);
 
        server = priority = 0;
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_get_xive(vcpu->kvm, irq, &server, &priority);
        else
                rc = kvmppc_xics_get_xive(vcpu->kvm, irq, &server, &priority);
@@ -83,7 +83,7 @@ static void kvm_rtas_int_off(struct kvm_vcpu *vcpu, struct rtas_args *args)
 
        irq = be32_to_cpu(args->args[0]);
 
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_int_off(vcpu->kvm, irq);
        else
                rc = kvmppc_xics_int_off(vcpu->kvm, irq);
@@ -105,7 +105,7 @@ static void kvm_rtas_int_on(struct kvm_vcpu *vcpu, struct rtas_args *args)
 
        irq = be32_to_cpu(args->args[0]);
 
-       if (xive_enabled())
+       if (xics_on_xive())
                rc = kvmppc_xive_int_on(vcpu->kvm, irq);
        else
                rc = kvmppc_xics_int_on(vcpu->kvm, irq);

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index b90a7d154180032d97efdb9150752d678453f9b3..8c69af10f91db3a1cc03f76e2aefde0fc45e367f 100644 (file)
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -748,7 +748,7 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
                kvmppc_mpic_disconnect_vcpu(vcpu->arch.mpic, vcpu);
                break;
        case KVMPPC_IRQ_XICS:
-               if (xive_enabled())
+               if (xics_on_xive())
                        kvmppc_xive_cleanup_vcpu(vcpu);
                else
                        kvmppc_xics_free_icp(vcpu);
@@ -1931,7 +1931,7 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
                r = -EPERM;
                dev = kvm_device_from_filp(f.file);
                if (dev) {
-                       if (xive_enabled())
+                       if (xics_on_xive())
                                r = kvmppc_xive_connect_vcpu(dev, vcpu, cap->args[1]);
                        else
                                r = kvmppc_xics_connect_vcpu(dev, vcpu, cap->args[1]);