path: root/target-ppc
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authorDavid Gibson <david@gibson.dropbear.id.au>2015-05-07 15:33:59 +1000
committerAlexander Graf <agraf@suse.de>2015-06-03 23:56:55 +0200
commit026bfd89cb896c8a3460cc551cc4836219bd7ff9 (patch)
tree0184f5e47dd4b528355f5bdfb9d381b3a760556d /target-ppc
parenta34944fe2e2457309bde74c1ffe3a1c60c6da018 (diff)
pseries: Enable in-kernel H_LOGICAL_CI_{LOAD, STORE} implementations
qemu currently implements the hypercalls H_LOGICAL_CI_LOAD and H_LOGICAL_CI_STORE as PAPR extensions. These are used by the SLOF firmware for IO, because performing cache inhibited MMIO accesses with the MMU off (real mode) is very awkward on POWER. This approach breaks when SLOF needs to access IO devices implemented within KVM instead of in qemu. The simplest example would be virtio-blk using an iothread, because the iothread / dataplane mechanism relies on an in-kernel implementation of the virtio queue notification MMIO. To fix this, an in-kernel implementation of these hypercalls has been made, (kernel commit 99342cf "kvmppc: Implement H_LOGICAL_CI_{LOAD,STORE} in KVM" however, the hypercalls still need to be enabled from qemu. This performs the necessary calls to do so. It would be nice to provide some warning if we encounter a problematic device with a kernel which doesn't support the new calls. Unfortunately, I can't see a way to detect this case which won't either warn in far too many cases that will probably work, or which is horribly invasive. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Thomas Huth <thuth@redhat.com> Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'target-ppc')
2 files changed, 22 insertions, 0 deletions
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 1da9ea81e5..97a50b1de3 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1884,6 +1884,23 @@ int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len)
return 0;
+static inline int kvmppc_enable_hcall(KVMState *s, target_ulong hcall)
+ return kvm_vm_enable_cap(s, KVM_CAP_PPC_ENABLE_HCALL, 0, hcall, 1);
+void kvmppc_enable_logical_ci_hcalls(void)
+ /*
+ * FIXME: it would be nice if we could detect the cases where
+ * we're using a device which requires the in kernel
+ * implementation of these hcalls, but the kernel lacks them and
+ * produce a warning.
+ */
+ kvmppc_enable_hcall(kvm_state, H_LOGICAL_CI_LOAD);
+ kvmppc_enable_hcall(kvm_state, H_LOGICAL_CI_STORE);
void kvmppc_set_papr(PowerPCCPU *cpu)
CPUState *cs = CPU(cpu);
diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index 2e0224c6af..4d30e27951 100644
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -24,6 +24,7 @@ bool kvmppc_get_host_serial(char **buf);
int kvmppc_get_hasidle(CPUPPCState *env);
int kvmppc_get_hypercall(CPUPPCState *env, uint8_t *buf, int buf_len);
int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int level);
+void kvmppc_enable_logical_ci_hcalls(void);
void kvmppc_set_papr(PowerPCCPU *cpu);
int kvmppc_set_compat(PowerPCCPU *cpu, uint32_t cpu_version);
void kvmppc_set_mpic_proxy(PowerPCCPU *cpu, int mpic_proxy);
@@ -107,6 +108,10 @@ static inline int kvmppc_set_interrupt(PowerPCCPU *cpu, int irq, int level)
return -1;
+static inline void kvmppc_enable_logical_ci_hcalls(void)
static inline void kvmppc_set_papr(PowerPCCPU *cpu)