@@ -28,6 +28,11 @@ S390:
property inside the device tree's /hypervisor node.
For more information refer to Documentation/virtual/kvm/ppc-pv.txt
+MIPS:
+ KVM hypercalls use the HYPCALL instruction with code 0 and the hypercall
+ number in $2 (v0). Up to four arguments may be placed in $4-$7 (a0-a3) and
+ the return value is placed in $2 (v0).
+
KVM Hypercalls Documentation
===========================
The template for each hypercall is:
@@ -229,6 +229,7 @@ enum emulation_result {
EMULATE_WAIT, /* WAIT instruction */
EMULATE_PRIV_FAIL,
EMULATE_EXCEPT, /* A guest exception has been generated */
+ EMULATE_HYPERCALL, /* HYPCALL instruction */
};
#define mips3_paddr_to_tlbpfn(x) \
@@ -832,6 +833,12 @@ unsigned int kvm_mips_config3_wrmask(struct kvm_vcpu *vcpu);
unsigned int kvm_mips_config4_wrmask(struct kvm_vcpu *vcpu);
unsigned int kvm_mips_config5_wrmask(struct kvm_vcpu *vcpu);
+/* Hypercalls (hypcall.c) */
+
+enum emulation_result kvm_mips_emul_hypcall(struct kvm_vcpu *vcpu,
+ union mips_instruction inst);
+int kvm_mips_handle_hypcall(struct kvm_vcpu *vcpu);
+
/* Dynamic binary translation */
extern int kvm_mips_trans_cache_index(union mips_instruction inst,
u32 *opc, struct kvm_vcpu *vcpu);
@@ -179,7 +179,7 @@ enum cop0_coi_func {
tlbr_op = 0x01, tlbwi_op = 0x02,
tlbwr_op = 0x06, tlbp_op = 0x08,
rfe_op = 0x10, eret_op = 0x18,
- wait_op = 0x20,
+ wait_op = 0x20, hypcall_op = 0x28
};
/*
@@ -10,6 +10,7 @@ common-objs-$(CONFIG_CPU_HAS_MSA) += msa.o
kvm-objs := $(common-objs-y) mips.o emulate.o entry.o \
interrupt.o stats.o commpage.o \
dyntrans.o trap_emul.o fpu.o
+kvm-objs += hypcall.o
kvm-objs += mmu.o
obj-$(CONFIG_KVM) += kvm.o
@@ -1143,6 +1143,9 @@ enum emulation_result kvm_mips_emulate_CP0(union mips_instruction inst,
case wait_op:
er = kvm_mips_emul_wait(vcpu);
break;
+ case hypcall_op:
+ er = kvm_mips_emul_hypcall(vcpu, inst);
+ break;
}
} else {
rt = inst.c0r_format.rt;
new file mode 100644
@@ -0,0 +1,53 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * KVM/MIPS: Hypercall handling.
+ *
+ * Copyright (C) 2015 Imagination Technologies Ltd.
+ */
+
+#include <linux/kernel.h>
+#include <linux/kvm_host.h>
+#include <linux/kvm_para.h>
+
+#define MAX_HYPCALL_ARGS 4
+
+enum emulation_result kvm_mips_emul_hypcall(struct kvm_vcpu *vcpu,
+ union mips_instruction inst)
+{
+ unsigned int code = (inst.co_format.code >> 5) & 0x3ff;
+
+ kvm_debug("[%#lx] HYPCALL %#03x\n", vcpu->arch.pc, code);
+
+ switch (code) {
+ case 0:
+ return EMULATE_HYPERCALL;
+ default:
+ return EMULATE_FAIL;
+ };
+}
+
+static int kvm_mips_hypercall(struct kvm_vcpu *vcpu, unsigned long num,
+ const unsigned long *args, unsigned long *hret)
+{
+ /* Report unimplemented hypercall to guest */
+ *hret = -KVM_ENOSYS;
+ return RESUME_GUEST;
+}
+
+int kvm_mips_handle_hypcall(struct kvm_vcpu *vcpu)
+{
+ unsigned long num, args[MAX_HYPCALL_ARGS];
+
+ /* read hypcall number and arguments */
+ num = vcpu->arch.gprs[2]; /* v0 */
+ args[0] = vcpu->arch.gprs[4]; /* a0 */
+ args[1] = vcpu->arch.gprs[5]; /* a1 */
+ args[2] = vcpu->arch.gprs[6]; /* a2 */
+ args[3] = vcpu->arch.gprs[7]; /* a3 */
+
+ return kvm_mips_hypercall(vcpu, num,
+ args, &vcpu->arch.gprs[2] /* v0 */);
+}
@@ -82,6 +82,10 @@ static int kvm_trap_emul_handle_cop_unusable(struct kvm_vcpu *vcpu)
ret = RESUME_HOST;
break;
+ case EMULATE_HYPERCALL:
+ ret = kvm_mips_handle_hypcall(vcpu);
+ break;
+
default:
BUG();
}
Emulate the HYPCALL instruction added in the VZ ASE and used by the MIPS paravirtualised guest support that is already merged. The new hypcall.c handles arguments and the return value, and will handle the individual hypercalls in upcoming commits. Non-zero HYPCALL codes are not handled. We also document the hypercall ABI which asm/kvm_para.h uses. Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: "Radim Krčmář" <rkrcmar@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Andreas Herrmann <andreas.herrmann@caviumnetworks.com> Cc: David Daney <david.daney@cavium.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: linux-mips@linux-mips.org Cc: kvm@vger.kernel.org Cc: linux-doc@vger.kernel.org --- Documentation/virtual/kvm/hypercalls.txt | 5 ++- arch/mips/include/asm/kvm_host.h | 7 +++- arch/mips/include/uapi/asm/inst.h | 2 +- arch/mips/kvm/Makefile | 1 +- arch/mips/kvm/emulate.c | 3 +- arch/mips/kvm/hypcall.c | 53 +++++++++++++++++++++++++- arch/mips/kvm/trap_emul.c | 4 ++- 7 files changed, 74 insertions(+), 1 deletion(-) create mode 100644 arch/mips/kvm/hypcall.c