diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 57d3ee9e4bde2a799715ca75871fd61b27858b0a..fc3ae951bc07e3d9f28553ece2bb1e62549b0155 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -3403,6 +3403,52 @@ invalid, if invalid pages are written to (e.g. after the end of memory)
or if no page table is present for the addresses (e.g. when using
hugepages).
+4.108 KVM_PPC_GET_CPU_CHAR
+
+Capability: KVM_CAP_PPC_GET_CPU_CHAR
+Architectures: powerpc
+Type: vm ioctl
+Parameters: struct kvm_ppc_cpu_char (out)
+Returns: 0 on successful completion
+ -EFAULT if struct kvm_ppc_cpu_char cannot be written
+
+This ioctl gives userspace information about certain characteristics
+of the CPU relating to speculative execution of instructions and
+possible information leakage resulting from speculative execution (see
+CVE-2017-5715, CVE-2017-5753 and CVE-2017-5754). The information is
+returned in struct kvm_ppc_cpu_char, which looks like this:
+
+struct kvm_ppc_cpu_char {
+ __u64 character; /* characteristics of the CPU */
+ __u64 behaviour; /* recommended software behaviour */
+ __u64 character_mask; /* valid bits in character */
+ __u64 behaviour_mask; /* valid bits in behaviour */
+};
+
+For extensibility, the character_mask and behaviour_mask fields
+indicate which bits of character and behaviour have been filled in by
+the kernel. If the set of defined bits is extended in future then
+userspace will be able to tell whether it is running on a kernel that
+knows about the new bits.
+
+The character field describes attributes of the CPU which can help
+with preventing inadvertent information disclosure - specifically,
+whether there is an instruction to flash-invalidate the L1 data cache
+(ori 30,30,0 or mtspr SPRN_TRIG2,rN), whether the L1 data cache is set
+to a mode where entries can only be used by the thread that created
+them, whether the bcctr[l] instruction prevents speculation, and
+whether a speculation barrier instruction (ori 31,31,0) is provided.
+
+The behaviour field describes actions that software should take to
+prevent inadvertent information disclosure, and thus describes which
+vulnerabilities the hardware is subject to; specifically whether the
+L1 data cache should be flushed when returning to user mode from the
+kernel, and whether a speculation barrier should be placed between an
+array bounds check and the array access.
+
+These fields use the same bit definitions as the new
+H_GET_CPU_CHARACTERISTICS hypercall.
+
5. The kvm_run structure
------------------------
diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
index 61d6049f4c1eced70ad3fef32f99b3a438da3eab..637b7263cb867f09618cc2a5e7b525686a0ea267 100644
--- a/arch/powerpc/include/uapi/asm/kvm.h
+++ b/arch/powerpc/include/uapi/asm/kvm.h
@@ -443,6 +443,31 @@ struct kvm_ppc_rmmu_info {
__u32 ap_encodings[8];
};
+/* For KVM_PPC_GET_CPU_CHAR */
+struct kvm_ppc_cpu_char {
+ __u64 character; /* characteristics of the CPU */
+ __u64 behaviour; /* recommended software behaviour */
+ __u64 character_mask; /* valid bits in character */
+ __u64 behaviour_mask; /* valid bits in behaviour */
+};
+
+/*
+ * Values for character and character_mask.
+ * These are identical to the values used by H_GET_CPU_CHARACTERISTICS.
+ */
+#define KVM_PPC_CPU_CHAR_SPEC_BAR_ORI31 (1ULL << 63)
+#define KVM_PPC_CPU_CHAR_BCCTRL_SERIALISED (1ULL << 62)
+#define KVM_PPC_CPU_CHAR_L1D_FLUSH_ORI30 (1ULL << 61)
+#define KVM_PPC_CPU_CHAR_L1D_FLUSH_TRIG2 (1ULL << 60)
+#define KVM_PPC_CPU_CHAR_L1D_THREAD_PRIV (1ULL << 59)
+#define KVM_PPC_CPU_CHAR_BR_HINT_HONOURED (1ULL << 58)
+#define KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF (1ULL << 57)
+#define KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS (1ULL << 56)
+
+#define KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY (1ULL << 63)
+#define KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR (1ULL << 62)
+#define KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR (1ULL << 61)
+
/* Per-vcpu XICS interrupt controller state */
#define KVM_REG_PPC_ICP_STATE (KVM_REG_PPC | KVM_REG_SIZE_U64 | 0x8c)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 1915e86cef6f8fc2e05852ddc7a0867eca1c560b..0a7c88786ec0e5d0a1ca07f2e9dc07502ea344b0 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -39,6 +39,10 @@
#include <asm/iommu.h>
#include <asm/switch_to.h>
#include <asm/xive.h>
+#ifdef CONFIG_PPC_PSERIES
+#include <asm/hvcall.h>
+#include <asm/plpar_wrappers.h>
+#endif
#include "timing.h"
#include "irq.h"
@@ -548,6 +552,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
#ifdef CONFIG_KVM_XICS
case KVM_CAP_IRQ_XICS:
#endif
+ case KVM_CAP_PPC_GET_CPU_CHAR:
r = 1;
break;
@@ -1759,6 +1764,124 @@ static int kvm_vm_ioctl_enable_cap(struct kvm *kvm,
return r;
}
+#ifdef CONFIG_PPC_BOOK3S_64
+/*
+ * These functions check whether the underlying hardware is safe
+ * against attacks based on observing the effects of speculatively
+ * executed instructions, and whether it supplies instructions for
+ * use in workarounds. The information comes from firmware, either
+ * via the device tree on powernv platforms or from an hcall on
+ * pseries platforms.
+ */
+#ifdef CONFIG_PPC_PSERIES
+static int pseries_get_cpu_char(struct kvm_ppc_cpu_char *cp)
+{
+ struct h_cpu_char_result c;
+ unsigned long rc;
+
+ if (!machine_is(pseries))
+ return -ENOTTY;
+
+ rc = plpar_get_cpu_characteristics(&c);
+ if (rc == H_SUCCESS) {
+ cp->character = c.character;
+ cp->behaviour = c.behaviour;
+ cp->character_mask = KVM_PPC_CPU_CHAR_SPEC_BAR_ORI31 |
+ KVM_PPC_CPU_CHAR_BCCTRL_SERIALISED |
+ KVM_PPC_CPU_CHAR_L1D_FLUSH_ORI30 |
+ KVM_PPC_CPU_CHAR_L1D_FLUSH_TRIG2 |
+ KVM_PPC_CPU_CHAR_L1D_THREAD_PRIV |
+ KVM_PPC_CPU_CHAR_BR_HINT_HONOURED |
+ KVM_PPC_CPU_CHAR_MTTRIG_THR_RECONF |
+ KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS;
+ cp->behaviour_mask = KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY |
+ KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR |
+ KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR;
+ }
+ return 0;
+}
+#else
+static int pseries_get_cpu_char(struct kvm_ppc_cpu_char *cp)
+{
+ return -ENOTTY;
+}
+#endif
+
+static inline bool have_fw_feat(struct device_node *fw_features,
+ const char *state, const char *name)
+{
+ struct device_node *np;
+ bool r = false;
+
+ np = of_get_child_by_name(fw_features, name);
+ if (np) {
+ r = of_property_read_bool(np, state);
+ of_node_put(np);
+ }
+ return r;
+}
+
+static int kvmppc_get_cpu_char(struct kvm_ppc_cpu_char *cp)
+{
+ struct device_node *np, *fw_features;
+ int r;
+
+ memset(cp, 0, sizeof(*cp));
+ r = pseries_get_cpu_char(cp);
+ if (r != -ENOTTY)
+ return r;
+
+ np = of_find_node_by_name(NULL, "ibm,opal");
+ if (np) {
+ fw_features = of_get_child_by_name(np, "fw-features");
+ of_node_put(np);
+ if (!fw_features)
+ return 0;
+ if (have_fw_feat(fw_features, "enabled",
+ "inst-spec-barrier-ori31,31,0"))
+ cp->character |= KVM_PPC_CPU_CHAR_SPEC_BAR_ORI31;
+ if (have_fw_feat(fw_features, "enabled",
+ "fw-bcctrl-serialized"))
+ cp->character |= KVM_PPC_CPU_CHAR_BCCTRL_SERIALISED;
+ if (have_fw_feat(fw_features, "enabled",
+ "inst-l1d-flush-ori30,30,0"))
+ cp->character |= KVM_PPC_CPU_CHAR_L1D_FLUSH_ORI30;
+ if (have_fw_feat(fw_features, "enabled",
+ "inst-l1d-flush-trig2"))
+ cp->character |= KVM_PPC_CPU_CHAR_L1D_FLUSH_TRIG2;
+ if (have_fw_feat(fw_features, "enabled",
+ "fw-l1d-thread-split"))
+ cp->character |= KVM_PPC_CPU_CHAR_L1D_THREAD_PRIV;
+ if (have_fw_feat(fw_features, "enabled",
+ "fw-count-cache-disabled"))
+ cp->character |= KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS;
+ cp->character_mask = KVM_PPC_CPU_CHAR_SPEC_BAR_ORI31 |
+ KVM_PPC_CPU_CHAR_BCCTRL_SERIALISED |
+ KVM_PPC_CPU_CHAR_L1D_FLUSH_ORI30 |
+ KVM_PPC_CPU_CHAR_L1D_FLUSH_TRIG2 |
+ KVM_PPC_CPU_CHAR_L1D_THREAD_PRIV |
+ KVM_PPC_CPU_CHAR_COUNT_CACHE_DIS;
+
+ if (have_fw_feat(fw_features, "enabled",
+ "speculation-policy-favor-security"))
+ cp->behaviour |= KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY;
+ if (!have_fw_feat(fw_features, "disabled",
+ "needs-l1d-flush-msr-pr-0-to-1"))
+ cp->behaviour |= KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR;
+ if (!have_fw_feat(fw_features, "disabled",
+ "needs-spec-barrier-for-bound-checks"))
+ cp->behaviour |= KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR;
+ cp->behaviour_mask = KVM_PPC_CPU_BEHAV_FAVOUR_SECURITY |
+ KVM_PPC_CPU_BEHAV_L1D_FLUSH_PR |
+ KVM_PPC_CPU_BEHAV_BNDS_CHK_SPEC_BAR;
+
+ of_node_put(fw_features);
+ }
+
+ return 0;
+}
+#endif
+
long kvm_arch_vm_ioctl(struct file *filp,
unsigned int ioctl, unsigned long arg)
{
@@ -1861,6 +1984,14 @@ long kvm_arch_vm_ioctl(struct file *filp,
r = -EFAULT;
break;
}
+ case KVM_PPC_GET_CPU_CHAR: {
+ struct kvm_ppc_cpu_char cpuchar;
+
+ r = kvmppc_get_cpu_char(&cpuchar);
+ if (r >= 0 && copy_to_user(argp, &cpuchar, sizeof(cpuchar)))
+ r = -EFAULT;
+ break;
+ }
default: {
struct kvm *kvm = filp->private_data;
r = kvm->arch.kvm_ops->arch_vm_ioctl(filp, ioctl, arg);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 496e59a2738ba99308f438e1f0509e66e17086cb..7a99b98cf88e32fdb85040b0cb6973f30ffbba0b 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -932,6 +932,7 @@ struct kvm_ppc_resize_hpt {
#define KVM_CAP_HYPERV_SYNIC2 148
#define KVM_CAP_HYPERV_VP_INDEX 149
#define KVM_CAP_S390_AIS_MIGRATION 150
+#define KVM_CAP_PPC_GET_CPU_CHAR 151
#ifdef KVM_CAP_IRQ_ROUTING
@@ -1261,6 +1262,8 @@ struct kvm_s390_ucas_mapping {
#define KVM_PPC_CONFIGURE_V3_MMU _IOW(KVMIO, 0xaf, struct kvm_ppc_mmuv3_cfg)
/* Available with KVM_CAP_PPC_RADIX_MMU */
#define KVM_PPC_GET_RMMU_INFO _IOW(KVMIO, 0xb0, struct kvm_ppc_rmmu_info)
+/* Available with KVM_CAP_PPC_GET_CPU_CHAR */
+#define KVM_PPC_GET_CPU_CHAR _IOR(KVMIO, 0xb1, struct kvm_ppc_cpu_char)
/* ioctl for vm fd */
#define KVM_CREATE_DEVICE _IOWR(KVMIO, 0xe0, struct kvm_create_device)