[PATCH v2 03/10] ARM: KVM: Initial VGIC MMIO support code

Christoffer Dall
2012-10-01T09:07:56Z

Wire the initial in-kernel MMIO support code for the VGIC, used
for the distributor emulation.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
---
arch/arm/include/asm/kvm_vgic.h | 6 +-
arch/arm/kvm/Makefile | 1
arch/arm/kvm/vgic.c | 138 +++++++++++++++++++++++++++++++++++++++
3 files changed, 144 insertions(+), 1 deletion(-)
create mode 100644 arch/arm/kvm/vgic.c

diff --git a/arch/arm/include/asm/kvm_vgic.h b/arch/arm/include/asm/kvm_vgic.h
index e1fd530..a87ec6c 100644
--- a/arch/arm/include/asm/kvm_vgic.h
+++ b/arch/arm/include/asm/kvm_vgic.h
@@ -30,7 +30,11 @@ struct kvm_vcpu;
struct kvm_run;
struct kvm_exit_mmio;

-#ifndef CONFIG_KVM_ARM_VGIC
+#ifdef CONFIG_KVM_ARM_VGIC
+bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
+ struct kvm_exit_mmio *mmio);
+
+#else
static inline int kvm_vgic_hyp_init(void)
{
return 0;
diff --git a/arch/arm/kvm/Makefile b/arch/arm/kvm/Makefile
index ea5b282..89608c0 100644
--- a/arch/arm/kvm/Makefile
+++ b/arch/arm/kvm/Makefile
@@ -20,3 +20,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += $(addprefix ../../../virt/kvm/, kvm_main.o coalesc

obj-$(CONFIG_KVM_ARM_HOST) += arm.o guest.o mmu.o emulate.o reset.o
obj-$(CONFIG_KVM_ARM_HOST) += coproc.o coproc_a15.o
+obj-$(CONFIG_KVM_ARM_VGIC) += vgic.o
diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
new file mode 100644
index 0000000..26ada3b
--- /dev/null
+++ b/arch/arm/kvm/vgic.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ * Author: Marc Zyngier <marc.zyngier@arm.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <asm/kvm_emulate.h>
+
+#define ACCESS_READ_VALUE (1 << 0)
+#define ACCESS_READ_RAZ (0 << 0)
+#define ACCESS_READ_MASK(x) ((x) & (1 << 0))
+#define ACCESS_WRITE_IGNORED (0 << 1)
+#define ACCESS_WRITE_SETBIT (1 << 1)
+#define ACCESS_WRITE_CLEARBIT (2 << 1)
+#define ACCESS_WRITE_VALUE (3 << 1)
+#define ACCESS_WRITE_MASK(x) ((x) & (3 << 1))
+
+/**
+ * vgic_reg_access - access vgic register
+ * @mmio: pointer to the data describing the mmio access
+ * @reg: pointer to the virtual backing of the vgic distributor struct
+ * @offset: least significant 2 bits used for word offset
+ * @mode: ACCESS_ mode (see defines above)
+ *
+ * Helper to make vgic register access easier using one of the access
+ * modes defined for vgic register access
+ * (read,raz,write-ignored,setbit,clearbit,write)
+ */
+static void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
+ u32 offset, int mode)
+{
+ int word_offset = offset & 3;
+ int shift = word_offset * 8;
+ u32 mask;
+ u32 regval;
+
+ /*
+ * Any alignment fault should have been delivered to the guest
+ * directly (ARM ARM B3.12.7 "Prioritization of aborts").
+ */
+
+ mask = (~0U) >> (word_offset * 8);
+ if (reg)
+ regval = *reg;
+ else {
+ BUG_ON(mode != (ACCESS_READ_RAZ | ACCESS_WRITE_IGNORED));
+ regval = 0;
+ }
+
+ if (mmio->is_write) {
+ u32 data = (*((u32 *)mmio->data) & mask) << shift;
+ switch (ACCESS_WRITE_MASK(mode)) {
+ case ACCESS_WRITE_IGNORED:
+ return;
+
+ case ACCESS_WRITE_SETBIT:
+ regval |= data;
+ break;
+
+ case ACCESS_WRITE_CLEARBIT:
+ regval &= ~data;
+ break;
+
+ case ACCESS_WRITE_VALUE:
+ regval = (regval & ~(mask << shift)) | data;
+ break;
+ }
+ *reg = regval;
+ } else {
+ switch (ACCESS_READ_MASK(mode)) {
+ case ACCESS_READ_RAZ:
+ regval = 0;
+ /* fall through */
+
+ case ACCESS_READ_VALUE:
+ *((u32 *)mmio->data) = (regval >> shift) & mask;
+ }
+ }
+}
+
+/* All this should be handled by kvm_bus_io_*()... FIXME!!! */
+struct mmio_range {
+ unsigned long base;
+ unsigned long len;
+ bool (*handle_mmio)(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
+ u32 offset);
+};
+
+static const struct mmio_range vgic_ranges[] = {
+ {}
+};
+
+static const
+struct mmio_range *find_matching_range(const struct mmio_range *ranges,
+ struct kvm_exit_mmio *mmio,
+ unsigned long base)
+{
+ const struct mmio_range *r = ranges;
+ unsigned long addr = mmio->phys_addr - base;
+
+ while (r->len) {
+ if (addr >= r->base &&
+ (addr + mmio->len) <= (r->base + r->len))
+ return r;
+ r++;
+ }
+
+ return NULL;
+}
+
+/**
+ * vgic_handle_mmio - handle an in-kernel MMIO access
+ * @vcpu: pointer to the vcpu performing the access
+ * @mmio: pointer to the data describing the access
+ *
+ * returns true if the MMIO access has been performed in kernel space,
+ * and false if it needs to be emulated in user space.
+ */
+bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_exit_mmio *mmio)
+{
+ return KVM_EXIT_MMIO;
+}