Some powerpc systems have support for a hardware random number generator
(hwrng). If such a hwrng is present the host kernel can provide access
to it via the H_RANDOM hcall.
The kernel advertises the presence of a hwrng with the KVM_CAP_PPC_HWRNG
capability. If this is detected we add the appropriate device tree bits
to advertise the presence of the hwrng to the guest kernel.
Signed-off-by: Michael Ellerman <mich...@ellerman.id.au>
---
hw/ppc/spapr.c | 16 ++++++++++++++++
include/hw/ppc/spapr.h | 1 +
linux-headers/linux/kvm.h | 1 +
target-ppc/kvm.c | 5 +++++
target-ppc/kvm_ppc.h | 5 +++++
5 files changed, 28 insertions(+)
diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 004184d..5909df1 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -497,6 +497,22 @@ static void *spapr_create_fdt_skel(const char *cpu_model,
_FDT((fdt_end_node(fdt)));
+ if (kvmppc_hwrng_present()) {
+ _FDT(fdt_begin_node(fdt, "ibm,platform-facilities"));
+
+ _FDT(fdt_property_string(fdt, "name", "ibm,platform-facilities"));
+ _FDT(fdt_property_string(fdt, "device_type",
+ "ibm,platform-facilities"));
+ _FDT(fdt_property_cell(fdt, "#address-cells", 0x1));
+ _FDT(fdt_property_cell(fdt, "#size-cells", 0x0));
+ _FDT(fdt_begin_node(fdt, "ibm,random-v1"));
+ _FDT(fdt_property_string(fdt, "name", "ibm,random-v1"));
+ _FDT(fdt_property_string(fdt, "compatible", "ibm,random"));
+ _FDT((fdt_end_node(fdt)));
+ }
+
+ _FDT((fdt_end_node(fdt)));
+
/* event-sources */
spapr_events_fdt_skel(fdt, epow_irq);
diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
index e37b419..c509500 100644
--- a/include/hw/ppc/spapr.h
+++ b/include/hw/ppc/spapr.h
@@ -283,6 +283,7 @@ typedef struct sPAPREnvironment {
#define H_GET_EM_PARMS 0x2B8
#define H_SET_MPP 0x2D0
#define H_GET_MPP 0x2D4
+#define H_RANDOM 0x300
#define H_SET_MODE 0x31C
#define MAX_HCALL_OPCODE H_SET_MODE
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index c614070..7be746c 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -666,6 +666,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_IRQ_MPIC 90
#define KVM_CAP_PPC_RTAS 91
#define KVM_CAP_IRQ_XICS 92
+#define KVM_CAP_PPC_HWRNG 95
#ifdef KVM_CAP_IRQ_ROUTING
diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
index 8a196c6..faf5dae 100644
--- a/target-ppc/kvm.c
+++ b/target-ppc/kvm.c
@@ -1875,3 +1875,8 @@ int kvm_arch_on_sigbus(int code, void *addr)
void kvm_arch_init_irq_routing(KVMState *s)
{
}
+
+bool kvmppc_hwrng_present(void)
+{
+ return kvm_enabled() && kvm_check_extension(kvm_state, KVM_CAP_PPC_HWRNG);
+}
diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
index 4ae7bf2..b7b898b 100644
--- a/target-ppc/kvm_ppc.h
+++ b/target-ppc/kvm_ppc.h
@@ -42,6 +42,7 @@ int kvmppc_get_htab_fd(bool write);
int kvmppc_save_htab(QEMUFile *f, int fd, size_t bufsize, int64_t max_ns);
int kvmppc_load_htab_chunk(QEMUFile *f, int fd, uint32_t index,
uint16_t n_valid, uint16_t n_invalid);
+bool kvmppc_hwrng_present(void);
#else
@@ -181,6 +182,10 @@ static inline int kvmppc_load_htab_chunk(QEMUFile *f, int
fd, uint32_t index,
abort();
}
+static inline bool kvmppc_hwrng_present(void)
+{
+ return false;
+}
#endif
#ifndef CONFIG_KVM
--
1.8.1.2
