[PATCH 3/3] KVM: PPC: Book3S: Add support for hwrng found on some powernv systems

Michael Ellerman
2013-09-26T06:31:58Z

Some powernv systems include a hwrng. Guests can access it via the
H_RANDOM hcall.

We add a real mode implementation of H_RANDOM when a hwrng is found.
Userspace can detect the presence of the hwrng by quering the
KVM_CAP_PPC_HWRNG capability.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
---
arch/powerpc/include/asm/archrandom.h | 11 ++-
arch/powerpc/include/asm/kvm_ppc.h | 2 +
arch/powerpc/kvm/book3s_hv_builtin.c | 15 ++++
arch/powerpc/kvm/book3s_hv_rmhandlers.S | 119 ++++++++++++++++++++++++++++++++
arch/powerpc/kvm/powerpc.c | 3 +
arch/powerpc/platforms/powernv/rng.c | 25 +++++++
include/uapi/linux/kvm.h | 1 +
7 files changed, 174 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/include/asm/archrandom.h b/arch/powerpc/include/asm/archrandom.h
index d853d16..86296d5 100644
--- a/arch/powerpc/include/asm/archrandom.h
+++ b/arch/powerpc/include/asm/archrandom.h
@@ -25,8 +25,15 @@ static inline int arch_get_random_int(unsigned int *v)
return rc;
}

-int powernv_get_random_long(unsigned long *v);
-
#endif /* CONFIG_ARCH_RANDOM */

+#ifdef CONFIG_PPC_POWERNV
+int powernv_hwrng_present(void);
+int powernv_get_random_long(unsigned long *v);
+int powernv_get_random_real_mode(unsigned long *v);
+#else
+static inline int powernv_hwrng_present(void) { return 0; }
+static inline int powernv_get_random_real_mode(unsigned long *v) { return 0; }
+#endif
+
#endif /* _ASM_POWERPC_ARCHRANDOM_H */
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
index b15554a..51966fd 100644
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -177,6 +177,8 @@ extern int kvmppc_xics_get_xive(struct kvm *kvm, u32 irq, u32 *server,
extern int kvmppc_xics_int_on(struct kvm *kvm, u32 irq);
extern int kvmppc_xics_int_off(struct kvm *kvm, u32 irq);

+extern int kvmppc_hwrng_present(void);
+
/*
* Cuts out inst bits with ordering according to spec.
* That means the leftmost bit is zero. All given bits are included.
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 8cd0dae..de12592 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -19,6 +19,7 @@
#include <asm/cputable.h>
#include <asm/kvm_ppc.h>
#include <asm/kvm_book3s.h>
+#include <asm/archrandom.h>

#include "book3s_hv_cma.h"
/*
@@ -181,3 +182,17 @@ void __init kvm_cma_reserve(void)
kvm_cma_declare_contiguous(selected_size, align_size);
}
}
+
+int kvmppc_hwrng_present(void)
+{
+ return powernv_hwrng_present();
+}
+EXPORT_SYMBOL_GPL(kvmppc_hwrng_present);
+
+long kvmppc_h_random(struct kvm_vcpu *vcpu)
+{
+ if (powernv_get_random_real_mode(&vcpu->arch.gpr[4]))
+ return H_SUCCESS;
+
+ return H_HARDWARE;
+}
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 294b7af..35ce59e 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1502,6 +1502,125 @@ hcall_real_table:
.long 0 /* 0x11c */
.long 0 /* 0x120 */
.long .kvmppc_h_bulk_remove - hcall_real_table
+ .long 0 /* 0x128 */
+ .long 0 /* 0x12c */
+ .long 0 /* 0x130 */
+ .long 0 /* 0x134 */
+ .long 0 /* 0x138 */
+ .long 0 /* 0x13c */
+ .long 0 /* 0x140 */
+ .long 0 /* 0x144 */
+ .long 0 /* 0x148 */
+ .long 0 /* 0x14c */
+ .long 0 /* 0x150 */
+ .long 0 /* 0x154 */
+ .long 0 /* 0x158 */
+ .long 0 /* 0x15c */
+ .long 0 /* 0x160 */
+ .long 0 /* 0x164 */
+ .long 0 /* 0x168 */
+ .long 0 /* 0x16c */
+ .long 0 /* 0x170 */
+ .long 0 /* 0x174 */
+ .long 0 /* 0x178 */
+ .long 0 /* 0x17c */
+ .long 0 /* 0x180 */
+ .long 0 /* 0x184 */
+ .long 0 /* 0x188 */
+ .long 0 /* 0x18c */
+ .long 0 /* 0x190 */
+ .long 0 /* 0x194 */
+ .long 0 /* 0x198 */
+ .long 0 /* 0x19c */
+ .long 0 /* 0x1a0 */
+ .long 0 /* 0x1a4 */
+ .long 0 /* 0x1a8 */
+ .long 0 /* 0x1ac */
+ .long 0 /* 0x1b0 */
+ .long 0 /* 0x1b4 */
+ .long 0 /* 0x1b8 */
+ .long 0 /* 0x1bc */
+ .long 0 /* 0x1c0 */
+ .long 0 /* 0x1c4 */
+ .long 0 /* 0x1c8 */
+ .long 0 /* 0x1cc */
+ .long 0 /* 0x1d0 */
+ .long 0 /* 0x1d4 */
+ .long 0 /* 0x1d8 */
+ .long 0 /* 0x1dc */
+ .long 0 /* 0x1e0 */
+ .long 0 /* 0x1e4 */
+ .long 0 /* 0x1e8 */
+ .long 0 /* 0x1ec */
+ .long 0 /* 0x1f0 */
+ .long 0 /* 0x1f4 */
+ .long 0 /* 0x1f8 */
+ .long 0 /* 0x1fc */
+ .long 0 /* 0x200 */
+ .long 0 /* 0x204 */
+ .long 0 /* 0x208 */
+ .long 0 /* 0x20c */
+ .long 0 /* 0x210 */
+ .long 0 /* 0x214 */
+ .long 0 /* 0x218 */
+ .long 0 /* 0x21c */
+ .long 0 /* 0x220 */
+ .long 0 /* 0x224 */
+ .long 0 /* 0x228 */
+ .long 0 /* 0x22c */
+ .long 0 /* 0x230 */
+ .long 0 /* 0x234 */
+ .long 0 /* 0x238 */
+ .long 0 /* 0x23c */
+ .long 0 /* 0x240 */
+ .long 0 /* 0x244 */
+ .long 0 /* 0x248 */
+ .long 0 /* 0x24c */
+ .long 0 /* 0x250 */
+ .long 0 /* 0x254 */
+ .long 0 /* 0x258 */
+ .long 0 /* 0x25c */
+ .long 0 /* 0x260 */
+ .long 0 /* 0x264 */
+ .long 0 /* 0x268 */
+ .long 0 /* 0x26c */
+ .long 0 /* 0x270 */
+ .long 0 /* 0x274 */
+ .long 0 /* 0x278 */
+ .long 0 /* 0x27c */
+ .long 0 /* 0x280 */
+ .long 0 /* 0x284 */
+ .long 0 /* 0x288 */
+ .long 0 /* 0x28c */
+ .long 0 /* 0x290 */
+ .long 0 /* 0x294 */
+ .long 0 /* 0x298 */
+ .long 0 /* 0x29c */
+ .long 0 /* 0x2a0 */
+ .long 0 /* 0x2a4 */
+ .long 0 /* 0x2a8 */
+ .long 0 /* 0x2ac */
+ .long 0 /* 0x2b0 */
+ .long 0 /* 0x2b4 */
+ .long 0 /* 0x2b8 */
+ .long 0 /* 0x2bc */
+ .long 0 /* 0x2c0 */
+ .long 0 /* 0x2c4 */
+ .long 0 /* 0x2c8 */
+ .long 0 /* 0x2cc */
+ .long 0 /* 0x2d0 */
+ .long 0 /* 0x2d4 */
+ .long 0 /* 0x2d8 */
+ .long 0 /* 0x2dc */
+ .long 0 /* 0x2e0 */
+ .long 0 /* 0x2e4 */
+ .long 0 /* 0x2e8 */
+ .long 0 /* 0x2ec */
+ .long 0 /* 0x2f0 */
+ .long 0 /* 0x2f4 */
+ .long 0 /* 0x2f8 */
+ .long 0 /* 0x2fc */
+ .long .kvmppc_h_random - hcall_real_table
hcall_real_table_end:

ignore_hdec:
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 07c0106..0d7208e 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -356,6 +356,9 @@ int kvm_dev_ioctl_check_extension(long ext)
if (cpu_has_feature(CPU_FTR_ARCH_201))
r = 2;
break;
+ case KVM_CAP_PPC_HWRNG:
+ r = kvmppc_hwrng_present();
+ break;
#endif
case KVM_CAP_SYNC_MMU:
#ifdef CONFIG_KVM_BOOK3S_64_HV
diff --git a/arch/powerpc/platforms/powernv/rng.c b/arch/powerpc/platforms/powernv/rng.c
index 51d2e6a..ea7e5cd 100644
--- a/arch/powerpc/platforms/powernv/rng.c
+++ b/arch/powerpc/platforms/powernv/rng.c
@@ -20,12 +20,18 @@

struct powernv_rng {
void __iomem *regs;
+ void __iomem *regs_real;
unsigned long mask;
};

static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);

+int powernv_hwrng_present(void)
+{
+ return __raw_get_cpu_var(powernv_rng) != NULL;
+}
+
static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
{
unsigned long parity;
@@ -42,6 +48,17 @@ static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
return val;
}

+int powernv_get_random_real_mode(unsigned long *v)
+{
+ struct powernv_rng *rng;
+
+ rng = __raw_get_cpu_var(powernv_rng);
+
+ *v = rng_whiten(rng, in_rm64(rng->regs_real));
+
+ return 1;
+}
+
int powernv_get_random_long(unsigned long *v)
{
struct powernv_rng *rng;
@@ -76,12 +93,20 @@ static __init void rng_init_per_cpu(struct powernv_rng *rng,
static __init int rng_create(struct device_node *dn)
{
struct powernv_rng *rng;
+ struct resource res;
unsigned long val;

rng = kzalloc(sizeof(*rng), GFP_KERNEL);
if (!rng)
return -ENOMEM;

+ if (of_address_to_resource(dn, 0, &res)) {
+ kfree(rng);
+ return -ENXIO;
+ }
+
+ rng->regs_real = (void __iomem *)res.start;
+
rng->regs = of_iomap(dn, 0);
if (!rng->regs) {
kfree(rng);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 99c2533..493a409 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -668,6 +668,7 @@ struct kvm_ppc_smmu_info {
#define KVM_CAP_IRQ_XICS 92
#define KVM_CAP_ARM_EL1_32BIT 93
#define KVM_CAP_SPAPR_MULTITCE 94
+#define KVM_CAP_PPC_HWRNG 95

#ifdef KVM_CAP_IRQ_ROUTING

--
1.8.1.2