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From:   Anup Patel <Anup.Patel@wdc.com>
To:     Palmer Dabbelt <palmer@sifive.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Radim K <rkrcmar@redhat.com>
CC:     Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Atish Patra <Atish.Patra@wdc.com>,
        Alistair Francis <Alistair.Francis@wdc.com>,
        Damien Le Moal <Damien.LeMoal@wdc.com>,
        Christoph Hellwig <hch@infradead.org>,
        Anup Patel <anup@brainfault.org>,
        "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
        "linux-riscv@lists.infradead.org" <linux-riscv@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Anup Patel <Anup.Patel@wdc.com>
Subject: [PATCH v4 18/20] RISC-V: KVM: Add SBI v0.1 support
Thread-Topic: [PATCH v4 18/20] RISC-V: KVM: Add SBI v0.1 support
Thread-Index: AQHVTRvI0V/1/jXIF064SLMkmSrnNA==
Date:   Wed, 7 Aug 2019 12:29:39 +0000
Message-ID: <20190807122726.81544-19-anup.patel@wdc.com>
References: <20190807122726.81544-1-anup.patel@wdc.com>
In-Reply-To: <20190807122726.81544-1-anup.patel@wdc.com>
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From: Atish Patra <atish.patra@wdc.com>

The KVM host kernel running in HS-mode needs to handle SBI calls coming
from guest kernel running in VS-mode.

This patch adds SBI v0.1 support in KVM RISC-V. All the SBI calls are
implemented correctly except remote tlb flushes. For remote TLB flushes,
we are doing full TLB flush and this will be optimized in future.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Signed-off-by: Anup Patel <anup.patel@wdc.com>
---
 arch/riscv/include/asm/kvm_host.h |   2 +
 arch/riscv/kvm/Makefile           |   2 +-
 arch/riscv/kvm/vcpu_exit.c        |   3 +
 arch/riscv/kvm/vcpu_sbi.c         | 119 ++++++++++++++++++++++++++++++
 4 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 arch/riscv/kvm/vcpu_sbi.c

diff --git a/arch/riscv/include/asm/kvm_host.h b/arch/riscv/include/asm/kvm=
_host.h
index 2af3a179c08e..0b1eceaef59f 100644
--- a/arch/riscv/include/asm/kvm_host.h
+++ b/arch/riscv/include/asm/kvm_host.h
@@ -241,4 +241,6 @@ bool kvm_riscv_vcpu_has_interrupt(struct kvm_vcpu *vcpu=
);
 void kvm_riscv_vcpu_power_off(struct kvm_vcpu *vcpu);
 void kvm_riscv_vcpu_power_on(struct kvm_vcpu *vcpu);
=20
+int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu);
+
 #endif /* __RISCV_KVM_HOST_H__ */
diff --git a/arch/riscv/kvm/Makefile b/arch/riscv/kvm/Makefile
index 3e0c7558320d..b56dc1650d2c 100644
--- a/arch/riscv/kvm/Makefile
+++ b/arch/riscv/kvm/Makefile
@@ -9,6 +9,6 @@ ccflags-y :=3D -Ivirt/kvm -Iarch/riscv/kvm
 kvm-objs :=3D $(common-objs-y)
=20
 kvm-objs +=3D main.o vm.o vmid.o tlb.o mmu.o
-kvm-objs +=3D vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o
+kvm-objs +=3D vcpu.o vcpu_exit.o vcpu_switch.o vcpu_timer.o vcpu_sbi.o
=20
 obj-$(CONFIG_KVM)	+=3D kvm.o
diff --git a/arch/riscv/kvm/vcpu_exit.c b/arch/riscv/kvm/vcpu_exit.c
index fbc04fe335ad..87b83fcf9a14 100644
--- a/arch/riscv/kvm/vcpu_exit.c
+++ b/arch/riscv/kvm/vcpu_exit.c
@@ -534,6 +534,9 @@ int kvm_riscv_vcpu_exit(struct kvm_vcpu *vcpu, struct k=
vm_run *run,
 		    (vcpu->arch.guest_context.hstatus & HSTATUS_STL))
 			ret =3D stage2_page_fault(vcpu, run, scause, stval);
 		break;
+	case EXC_SUPERVISOR_SYSCALL:
+		if (vcpu->arch.guest_context.hstatus & HSTATUS_SPV)
+			ret =3D kvm_riscv_vcpu_sbi_ecall(vcpu);
 	default:
 		break;
 	};
diff --git a/arch/riscv/kvm/vcpu_sbi.c b/arch/riscv/kvm/vcpu_sbi.c
new file mode 100644
index 000000000000..5793202eb514
--- /dev/null
+++ b/arch/riscv/kvm/vcpu_sbi.c
@@ -0,0 +1,119 @@
+// SPDX-License-Identifier: GPL-2.0
+/**
+ * Copyright (c) 2019 Western Digital Corporation or its affiliates.
+ *
+ * Authors:
+ *     Atish Patra <atish.patra@wdc.com>
+ */
+
+#include <linux/errno.h>
+#include <linux/err.h>
+#include <linux/kvm_host.h>
+#include <asm/csr.h>
+#include <asm/kvm_vcpu_timer.h>
+
+#define SBI_VERSION_MAJOR			0
+#define SBI_VERSION_MINOR			1
+
+/* TODO: Handle traps due to unpriv load and redirect it back to VS-mode *=
/
+static unsigned long kvm_sbi_unpriv_load(const unsigned long *addr,
+					 struct kvm_vcpu *vcpu)
+{
+	unsigned long flags, val;
+	unsigned long __hstatus, __sstatus;
+
+	local_irq_save(flags);
+	__hstatus =3D csr_read(CSR_HSTATUS);
+	__sstatus =3D csr_read(CSR_SSTATUS);
+	csr_write(CSR_HSTATUS, vcpu->arch.guest_context.hstatus | HSTATUS_SPRV);
+	csr_write(CSR_SSTATUS, vcpu->arch.guest_context.sstatus);
+	val =3D *addr;
+	csr_write(CSR_HSTATUS, __hstatus);
+	csr_write(CSR_SSTATUS, __sstatus);
+	local_irq_restore(flags);
+
+	return val;
+}
+
+static void kvm_sbi_system_shutdown(struct kvm_vcpu *vcpu, u32 type)
+{
+	int i;
+	struct kvm_vcpu *tmp;
+
+	kvm_for_each_vcpu(i, tmp, vcpu->kvm)
+		tmp->arch.power_off =3D true;
+	kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
+
+	memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
+	vcpu->run->system_event.type =3D type;
+	vcpu->run->exit_reason =3D KVM_EXIT_SYSTEM_EVENT;
+}
+
+int kvm_riscv_vcpu_sbi_ecall(struct kvm_vcpu *vcpu)
+{
+	int ret =3D 1;
+	u64 next_cycle;
+	int vcpuid;
+	struct kvm_vcpu *remote_vcpu;
+	ulong dhart_mask;
+	struct kvm_cpu_context *cp =3D &vcpu->arch.guest_context;
+
+	if (!cp)
+		return -EINVAL;
+	switch (cp->a7) {
+	case SBI_SET_TIMER:
+#if __riscv_xlen =3D=3D 32
+		next_cycle =3D ((u64)cp->a1 << 32) | (u64)cp->a0;
+#else
+		next_cycle =3D (u64)cp->a0;
+#endif
+		kvm_riscv_vcpu_timer_next_event(vcpu, next_cycle);
+		break;
+	case SBI_CONSOLE_PUTCHAR:
+		/* Not implemented */
+		cp->a0 =3D -ENOTSUPP;
+		break;
+	case SBI_CONSOLE_GETCHAR:
+		/* Not implemented */
+		cp->a0 =3D -ENOTSUPP;
+		break;
+	case SBI_CLEAR_IPI:
+		kvm_riscv_vcpu_unset_interrupt(vcpu, IRQ_S_SOFT);
+		break;
+	case SBI_SEND_IPI:
+		dhart_mask =3D kvm_sbi_unpriv_load((unsigned long *)cp->a0, vcpu);
+		for_each_set_bit(vcpuid, &dhart_mask, BITS_PER_LONG) {
+			remote_vcpu =3D kvm_get_vcpu_by_id(vcpu->kvm, vcpuid);
+			kvm_riscv_vcpu_set_interrupt(remote_vcpu, IRQ_S_SOFT);
+		}
+		break;
+	case SBI_SHUTDOWN:
+		kvm_sbi_system_shutdown(vcpu, KVM_SYSTEM_EVENT_SHUTDOWN);
+		ret =3D 0;
+		break;
+	case SBI_REMOTE_FENCE_I:
+		sbi_remote_fence_i(NULL);
+		break;
+	/*
+	 * TODO: There should be a way to call remote hfence.bvma.
+	 * Preferred method is now a SBI call. Until then, just flush
+	 * all tlbs.
+	 */
+	case SBI_REMOTE_SFENCE_VMA:
+		/*TODO: Parse vma range.*/
+		sbi_remote_sfence_vma(NULL, 0, 0);
+		break;
+	case SBI_REMOTE_SFENCE_VMA_ASID:
+		/*TODO: Parse vma range for given ASID */
+		sbi_remote_sfence_vma(NULL, 0, 0);
+		break;
+	default:
+		cp->a0 =3D ENOTSUPP;
+		break;
+	};
+
+	if (ret >=3D 0)
+		cp->sepc +=3D 4;
+
+	return ret;
+}
--=20
2.17.1