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-rw-r--r--virt/kvm/arm/vgic/vgic-mmio.c526
1 files changed, 526 insertions, 0 deletions
diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
new file mode 100644
index 000000000000..059595ec3da0
--- /dev/null
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -0,0 +1,526 @@
+/*
+ * VGIC MMIO handling functions
+ *
+ * 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.
+ */
+
+#include <linux/bitops.h>
+#include <linux/bsearch.h>
+#include <linux/kvm.h>
+#include <linux/kvm_host.h>
+#include <kvm/iodev.h>
+#include <kvm/arm_vgic.h>
+
+#include "vgic.h"
+#include "vgic-mmio.h"
+
+unsigned long vgic_mmio_read_raz(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ return 0;
+}
+
+unsigned long vgic_mmio_read_rao(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ return -1UL;
+}
+
+void vgic_mmio_write_wi(struct kvm_vcpu *vcpu, gpa_t addr,
+ unsigned int len, unsigned long val)
+{
+ /* Ignore */
+}
+
+/*
+ * Read accesses to both GICD_ICENABLER and GICD_ISENABLER return the value
+ * of the enabled bit, so there is only one function for both here.
+ */
+unsigned long vgic_mmio_read_enable(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ u32 value = 0;
+ int i;
+
+ /* Loop over all IRQs affected by this read */
+ for (i = 0; i < len * 8; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ if (irq->enabled)
+ value |= (1U << i);
+ }
+
+ return value;
+}
+
+void vgic_mmio_write_senable(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+ irq->enabled = true;
+ vgic_queue_irq_unlock(vcpu->kvm, irq);
+ }
+}
+
+void vgic_mmio_write_cenable(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+
+ irq->enabled = false;
+
+ spin_unlock(&irq->irq_lock);
+ }
+}
+
+unsigned long vgic_mmio_read_pending(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ u32 value = 0;
+ int i;
+
+ /* Loop over all IRQs affected by this read */
+ for (i = 0; i < len * 8; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ if (irq->pending)
+ value |= (1U << i);
+ }
+
+ return value;
+}
+
+void vgic_mmio_write_spending(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+ irq->pending = true;
+ if (irq->config == VGIC_CONFIG_LEVEL)
+ irq->soft_pending = true;
+
+ vgic_queue_irq_unlock(vcpu->kvm, irq);
+ }
+}
+
+void vgic_mmio_write_cpending(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+
+ if (irq->config == VGIC_CONFIG_LEVEL) {
+ irq->soft_pending = false;
+ irq->pending = irq->line_level;
+ } else {
+ irq->pending = false;
+ }
+
+ spin_unlock(&irq->irq_lock);
+ }
+}
+
+unsigned long vgic_mmio_read_active(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ u32 value = 0;
+ int i;
+
+ /* Loop over all IRQs affected by this read */
+ for (i = 0; i < len * 8; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ if (irq->active)
+ value |= (1U << i);
+ }
+
+ return value;
+}
+
+static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
+ bool new_active_state)
+{
+ spin_lock(&irq->irq_lock);
+ /*
+ * If this virtual IRQ was written into a list register, we
+ * have to make sure the CPU that runs the VCPU thread has
+ * synced back LR state to the struct vgic_irq. We can only
+ * know this for sure, when either this irq is not assigned to
+ * anyone's AP list anymore, or the VCPU thread is not
+ * running on any CPUs.
+ *
+ * In the opposite case, we know the VCPU thread may be on its
+ * way back from the guest and still has to sync back this
+ * IRQ, so we release and re-acquire the spin_lock to let the
+ * other thread sync back the IRQ.
+ */
+ while (irq->vcpu && /* IRQ may have state in an LR somewhere */
+ irq->vcpu->cpu != -1) { /* VCPU thread is running */
+ BUG_ON(irq->intid < VGIC_NR_PRIVATE_IRQS);
+ cond_resched_lock(&irq->irq_lock);
+ }
+
+ irq->active = new_active_state;
+ if (new_active_state)
+ vgic_queue_irq_unlock(vcpu->kvm, irq);
+ else
+ spin_unlock(&irq->irq_lock);
+}
+
+/*
+ * If we are fiddling with an IRQ's active state, we have to make sure the IRQ
+ * is not queued on some running VCPU's LRs, because then the change to the
+ * active state can be overwritten when the VCPU's state is synced coming back
+ * from the guest.
+ *
+ * For shared interrupts, we have to stop all the VCPUs because interrupts can
+ * be migrated while we don't hold the IRQ locks and we don't want to be
+ * chasing moving targets.
+ *
+ * For private interrupts, we only have to make sure the single and only VCPU
+ * that can potentially queue the IRQ is stopped.
+ */
+static void vgic_change_active_prepare(struct kvm_vcpu *vcpu, u32 intid)
+{
+ if (intid < VGIC_NR_PRIVATE_IRQS)
+ kvm_arm_halt_vcpu(vcpu);
+ else
+ kvm_arm_halt_guest(vcpu->kvm);
+}
+
+/* See vgic_change_active_prepare */
+static void vgic_change_active_finish(struct kvm_vcpu *vcpu, u32 intid)
+{
+ if (intid < VGIC_NR_PRIVATE_IRQS)
+ kvm_arm_resume_vcpu(vcpu);
+ else
+ kvm_arm_resume_guest(vcpu->kvm);
+}
+
+void vgic_mmio_write_cactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ vgic_change_active_prepare(vcpu, intid);
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+ vgic_mmio_change_active(vcpu, irq, false);
+ }
+ vgic_change_active_finish(vcpu, intid);
+}
+
+void vgic_mmio_write_sactive(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 1);
+ int i;
+
+ vgic_change_active_prepare(vcpu, intid);
+ for_each_set_bit(i, &val, len * 8) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+ vgic_mmio_change_active(vcpu, irq, true);
+ }
+ vgic_change_active_finish(vcpu, intid);
+}
+
+unsigned long vgic_mmio_read_priority(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
+ int i;
+ u64 val = 0;
+
+ for (i = 0; i < len; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ val |= (u64)irq->priority << (i * 8);
+ }
+
+ return val;
+}
+
+/*
+ * We currently don't handle changing the priority of an interrupt that
+ * is already pending on a VCPU. If there is a need for this, we would
+ * need to make this VCPU exit and re-evaluate the priorities, potentially
+ * leading to this interrupt getting presented now to the guest (if it has
+ * been masked by the priority mask before).
+ */
+void vgic_mmio_write_priority(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 8);
+ int i;
+
+ for (i = 0; i < len; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ spin_lock(&irq->irq_lock);
+ /* Narrow the priority range to what we actually support */
+ irq->priority = (val >> (i * 8)) & GENMASK(7, 8 - VGIC_PRI_BITS);
+ spin_unlock(&irq->irq_lock);
+ }
+}
+
+unsigned long vgic_mmio_read_config(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 2);
+ u32 value = 0;
+ int i;
+
+ for (i = 0; i < len * 4; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ if (irq->config == VGIC_CONFIG_EDGE)
+ value |= (2U << (i * 2));
+ }
+
+ return value;
+}
+
+void vgic_mmio_write_config(struct kvm_vcpu *vcpu,
+ gpa_t addr, unsigned int len,
+ unsigned long val)
+{
+ u32 intid = VGIC_ADDR_TO_INTID(addr, 2);
+ int i;
+
+ for (i = 0; i < len * 4; i++) {
+ struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, intid + i);
+
+ /*
+ * The configuration cannot be changed for SGIs in general,
+ * for PPIs this is IMPLEMENTATION DEFINED. The arch timer
+ * code relies on PPIs being level triggered, so we also
+ * make them read-only here.
+ */
+ if (intid + i < VGIC_NR_PRIVATE_IRQS)
+ continue;
+
+ spin_lock(&irq->irq_lock);
+ if (test_bit(i * 2 + 1, &val)) {
+ irq->config = VGIC_CONFIG_EDGE;
+ } else {
+ irq->config = VGIC_CONFIG_LEVEL;
+ irq->pending = irq->line_level | irq->soft_pending;
+ }
+ spin_unlock(&irq->irq_lock);
+ }
+}
+
+static int match_region(const void *key, const void *elt)
+{
+ const unsigned int offset = (unsigned long)key;
+ const struct vgic_register_region *region = elt;
+
+ if (offset < region->reg_offset)
+ return -1;
+
+ if (offset >= region->reg_offset + region->len)
+ return 1;
+
+ return 0;
+}
+
+/* Find the proper register handler entry given a certain address offset. */
+static const struct vgic_register_region *
+vgic_find_mmio_region(const struct vgic_register_region *region, int nr_regions,
+ unsigned int offset)
+{
+ return bsearch((void *)(uintptr_t)offset, region, nr_regions,
+ sizeof(region[0]), match_region);
+}
+
+/*
+ * kvm_mmio_read_buf() returns a value in a format where it can be converted
+ * to a byte array and be directly observed as the guest wanted it to appear
+ * in memory if it had done the store itself, which is LE for the GIC, as the
+ * guest knows the GIC is always LE.
+ *
+ * We convert this value to the CPUs native format to deal with it as a data
+ * value.
+ */
+unsigned long vgic_data_mmio_bus_to_host(const void *val, unsigned int len)
+{
+ unsigned long data = kvm_mmio_read_buf(val, len);
+
+ switch (len) {
+ case 1:
+ return data;
+ case 2:
+ return le16_to_cpu(data);
+ case 4:
+ return le32_to_cpu(data);
+ default:
+ return le64_to_cpu(data);
+ }
+}
+
+/*
+ * kvm_mmio_write_buf() expects a value in a format such that if converted to
+ * a byte array it is observed as the guest would see it if it could perform
+ * the load directly. Since the GIC is LE, and the guest knows this, the
+ * guest expects a value in little endian format.
+ *
+ * We convert the data value from the CPUs native format to LE so that the
+ * value is returned in the proper format.
+ */
+void vgic_data_host_to_mmio_bus(void *buf, unsigned int len,
+ unsigned long data)
+{
+ switch (len) {
+ case 1:
+ break;
+ case 2:
+ data = cpu_to_le16(data);
+ break;
+ case 4:
+ data = cpu_to_le32(data);
+ break;
+ default:
+ data = cpu_to_le64(data);
+ }
+
+ kvm_mmio_write_buf(buf, len, data);
+}
+
+static
+struct vgic_io_device *kvm_to_vgic_iodev(const struct kvm_io_device *dev)
+{
+ return container_of(dev, struct vgic_io_device, dev);
+}
+
+static bool check_region(const struct vgic_register_region *region,
+ gpa_t addr, int len)
+{
+ if ((region->access_flags & VGIC_ACCESS_8bit) && len == 1)
+ return true;
+ if ((region->access_flags & VGIC_ACCESS_32bit) &&
+ len == sizeof(u32) && !(addr & 3))
+ return true;
+ if ((region->access_flags & VGIC_ACCESS_64bit) &&
+ len == sizeof(u64) && !(addr & 7))
+ return true;
+
+ return false;
+}
+
+static int dispatch_mmio_read(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, void *val)
+{
+ struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+ const struct vgic_register_region *region;
+ struct kvm_vcpu *r_vcpu;
+ unsigned long data;
+
+ region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
+ addr - iodev->base_addr);
+ if (!region || !check_region(region, addr, len)) {
+ memset(val, 0, len);
+ return 0;
+ }
+
+ r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+ data = region->read(r_vcpu, addr, len);
+ vgic_data_host_to_mmio_bus(val, len, data);
+ return 0;
+}
+
+static int dispatch_mmio_write(struct kvm_vcpu *vcpu, struct kvm_io_device *dev,
+ gpa_t addr, int len, const void *val)
+{
+ struct vgic_io_device *iodev = kvm_to_vgic_iodev(dev);
+ const struct vgic_register_region *region;
+ struct kvm_vcpu *r_vcpu;
+ unsigned long data = vgic_data_mmio_bus_to_host(val, len);
+
+ region = vgic_find_mmio_region(iodev->regions, iodev->nr_regions,
+ addr - iodev->base_addr);
+ if (!region)
+ return 0;
+
+ if (!check_region(region, addr, len))
+ return 0;
+
+ r_vcpu = iodev->redist_vcpu ? iodev->redist_vcpu : vcpu;
+ region->write(r_vcpu, addr, len, data);
+ return 0;
+}
+
+struct kvm_io_device_ops kvm_io_gic_ops = {
+ .read = dispatch_mmio_read,
+ .write = dispatch_mmio_write,
+};
+
+int vgic_register_dist_iodev(struct kvm *kvm, gpa_t dist_base_address,
+ enum vgic_type type)
+{
+ struct vgic_io_device *io_device = &kvm->arch.vgic.dist_iodev;
+ int ret = 0;
+ unsigned int len;
+
+ switch (type) {
+ case VGIC_V2:
+ len = vgic_v2_init_dist_iodev(io_device);
+ break;
+#ifdef CONFIG_KVM_ARM_VGIC_V3
+ case VGIC_V3:
+ len = vgic_v3_init_dist_iodev(io_device);
+ break;
+#endif
+ default:
+ BUG_ON(1);
+ }
+
+ io_device->base_addr = dist_base_address;
+ io_device->redist_vcpu = NULL;
+
+ mutex_lock(&kvm->slots_lock);
+ ret = kvm_io_bus_register_dev(kvm, KVM_MMIO_BUS, dist_base_address,
+ len, &io_device->dev);
+ mutex_unlock(&kvm->slots_lock);
+
+ return ret;
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.