KVM: PPC: Book3S: Controls for in-kernel sPAPR hypercall handling
This provides a way for userspace controls which sPAPR hcalls get
handled in the kernel. Each hcall can be individually enabled or
disabled for in-kernel handling, except for H_RTAS. The exception
for H_RTAS is because userspace can already control whether
individual RTAS functions are handled in-kernel or not via the
KVM_PPC_RTAS_DEFINE_TOKEN ioctl, and because the numeric value for
H_RTAS is out of the normal sequence of hcall numbers.
Hcalls are enabled or disabled using the KVM_ENABLE_CAP ioctl for the
KVM_CAP_PPC_ENABLE_HCALL capability on the file descriptor for the VM.
The args field of the struct kvm_enable_cap specifies the hcall number
in args[0] and the enable/disable flag in args[1]; 0 means disable
in-kernel handling (so that the hcall will always cause an exit to
userspace) and 1 means enable. Enabling or disabling in-kernel
handling of an hcall is effective across the whole VM.
The ability for KVM_ENABLE_CAP to be used on a VM file descriptor
on PowerPC is new, added by this commit. The KVM_CAP_ENABLE_CAP_VM
capability advertises that this ability exists.
When a VM is created, an initial set of hcalls are enabled for
in-kernel handling. The set that is enabled is the set that have
an in-kernel implementation at this point. Any new hcall
implementations from this point onwards should not be added to the
default set without a good reason.
No distinction is made between real-mode and virtual-mode hcall
implementations; the one setting controls them both.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
diff --git a/arch/powerpc/kvm/book3s_hv.c b/arch/powerpc/kvm/book3s_hv.c
index 1562acf..cf445d2 100644
--- a/arch/powerpc/kvm/book3s_hv.c
+++ b/arch/powerpc/kvm/book3s_hv.c
@@ -67,6 +67,8 @@
/* Used as a "null" value for timebase values */
#define TB_NIL (~(u64)0)
+static DECLARE_BITMAP(default_enabled_hcalls, MAX_HCALL_OPCODE/4 + 1);
+
static void kvmppc_end_cede(struct kvm_vcpu *vcpu);
static int kvmppc_hv_setup_htab_rma(struct kvm_vcpu *vcpu);
@@ -562,6 +564,10 @@
struct kvm_vcpu *tvcpu;
int idx, rc;
+ if (req <= MAX_HCALL_OPCODE &&
+ !test_bit(req/4, vcpu->kvm->arch.enabled_hcalls))
+ return RESUME_HOST;
+
switch (req) {
case H_ENTER:
idx = srcu_read_lock(&vcpu->kvm->srcu);
@@ -2269,6 +2275,10 @@
*/
cpumask_setall(&kvm->arch.need_tlb_flush);
+ /* Start out with the default set of hcalls enabled */
+ memcpy(kvm->arch.enabled_hcalls, default_enabled_hcalls,
+ sizeof(kvm->arch.enabled_hcalls));
+
kvm->arch.rma = NULL;
kvm->arch.host_sdr1 = mfspr(SPRN_SDR1);
@@ -2407,6 +2417,45 @@
return r;
}
+/*
+ * List of hcall numbers to enable by default.
+ * For compatibility with old userspace, we enable by default
+ * all hcalls that were implemented before the hcall-enabling
+ * facility was added. Note this list should not include H_RTAS.
+ */
+static unsigned int default_hcall_list[] = {
+ H_REMOVE,
+ H_ENTER,
+ H_READ,
+ H_PROTECT,
+ H_BULK_REMOVE,
+ H_GET_TCE,
+ H_PUT_TCE,
+ H_SET_DABR,
+ H_SET_XDABR,
+ H_CEDE,
+ H_PROD,
+ H_CONFER,
+ H_REGISTER_VPA,
+#ifdef CONFIG_KVM_XICS
+ H_EOI,
+ H_CPPR,
+ H_IPI,
+ H_IPOLL,
+ H_XIRR,
+ H_XIRR_X,
+#endif
+ 0
+};
+
+static void init_default_hcalls(void)
+{
+ int i;
+
+ for (i = 0; default_hcall_list[i]; ++i)
+ __set_bit(default_hcall_list[i] / 4, default_enabled_hcalls);
+}
+
static struct kvmppc_ops kvm_ops_hv = {
.get_sregs = kvm_arch_vcpu_ioctl_get_sregs_hv,
.set_sregs = kvm_arch_vcpu_ioctl_set_sregs_hv,
@@ -2454,6 +2503,8 @@
kvm_ops_hv.owner = THIS_MODULE;
kvmppc_hv_ops = &kvm_ops_hv;
+ init_default_hcalls();
+
r = kvmppc_mmu_hv_init();
return r;
}