[PATCH v13 20/24] virt: gunyah: Add proxy-scheduled vCPUs
Elliot Berman
quic_eberman at quicinc.com
Tue May 9 13:47:57 PDT 2023
Gunyah allows host virtual machines to schedule guest virtual machines
and handle their MMIO accesses. vCPUs are presented to the host as a
Gunyah resource and represented to userspace as a Gunyah VM function.
Creating the vcpu VM function will create a file descriptor that:
- can run an ioctl: GH_VCPU_RUN to schedule the guest vCPU until the
next interrupt occurs on the host or when the guest vCPU can no
longer be run.
- can be mmap'd to share a gh_vcpu_run structure which can look up the
reason why GH_VCPU_RUN returned and provide return values for MMIO
access.
Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu at quicinc.com>
Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu at quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman at quicinc.com>
---
Documentation/virt/gunyah/vm-manager.rst | 46 ++-
arch/arm64/gunyah/gunyah_hypercall.c | 28 ++
drivers/virt/gunyah/Kconfig | 11 +
drivers/virt/gunyah/Makefile | 2 +
drivers/virt/gunyah/gunyah_vcpu.c | 468 +++++++++++++++++++++++
drivers/virt/gunyah/vm_mgr.c | 4 +
drivers/virt/gunyah/vm_mgr.h | 1 +
include/linux/gunyah.h | 24 ++
include/uapi/linux/gunyah.h | 128 +++++++
9 files changed, 710 insertions(+), 2 deletions(-)
create mode 100644 drivers/virt/gunyah/gunyah_vcpu.c
diff --git a/Documentation/virt/gunyah/vm-manager.rst b/Documentation/virt/gunyah/vm-manager.rst
index 3b51bab9d793..6789d13fed14 100644
--- a/Documentation/virt/gunyah/vm-manager.rst
+++ b/Documentation/virt/gunyah/vm-manager.rst
@@ -5,8 +5,7 @@ Virtual Machine Manager
=======================
The Gunyah Virtual Machine Manager is a Linux driver to support launching
-virtual machines using Gunyah. It presently supports launching non-proxy
-scheduled Linux-like virtual machines.
+virtual machines using Gunyah.
Except for some basic information about the location of initial binaries,
most of the configuration about a Gunyah virtual machine is described in the
@@ -98,3 +97,46 @@ GH_VM_START
~~~~~~~~~~~
This ioctl starts the VM.
+
+GH_VM_ADD_FUNCTION
+~~~~~~~~~~~~~~~~~~
+
+This ioctl registers a Gunyah VM function with the VM manager. The VM function
+is described with a &struct gh_fn_desc.type and some arguments for that type.
+Typically, the function is added before the VM starts, but the function doesn't
+"operate" until the VM starts with `GH_VM_START`_. For example, vCPU ioclts will
+all return an error until the VM starts because the vCPUs don't exist until the
+VM is started. This allows the VMM to set up all the kernel functions needed for
+the VM *before* the VM starts.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+ :identifiers: gh_fn_desc gh_fn_type
+
+The argument types are documented below:
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+ :identifiers: gh_fn_vcpu_arg
+
+Gunyah VCPU API Descriptions
+----------------------------
+
+A vCPU file descriptor is created after calling `GH_VM_ADD_FUNCTION` with the type `GH_FN_VCPU`.
+
+GH_VCPU_RUN
+~~~~~~~~~~~
+
+This ioctl is used to run a guest virtual cpu. While there are no
+explicit parameters, there is an implicit parameter block that can be
+obtained by mmap()ing the vcpu fd at offset 0, with the size given by
+`GH_VCPU_MMAP_SIZE`_. The parameter block is formatted as a 'struct
+gh_vcpu_run' (see below).
+
+GH_VCPU_MMAP_SIZE
+~~~~~~~~~~~~~~~~~
+
+The `GH_VCPU_RUN`_ ioctl communicates with userspace via a shared
+memory region. This ioctl returns the size of that region. See the
+`GH_VCPU_RUN`_ documentation for details.
+
+.. kernel-doc:: include/uapi/linux/gunyah.h
+ :identifiers: gh_vcpu_exit gh_vcpu_run gh_vm_status gh_vm_exit_info
diff --git a/arch/arm64/gunyah/gunyah_hypercall.c b/arch/arm64/gunyah/gunyah_hypercall.c
index 2b2a63e9b9e5..5f33f53e05a9 100644
--- a/arch/arm64/gunyah/gunyah_hypercall.c
+++ b/arch/arm64/gunyah/gunyah_hypercall.c
@@ -35,6 +35,7 @@ EXPORT_SYMBOL_GPL(arch_is_gh_guest);
#define GH_HYPERCALL_HYP_IDENTIFY GH_HYPERCALL(0x8000)
#define GH_HYPERCALL_MSGQ_SEND GH_HYPERCALL(0x801B)
#define GH_HYPERCALL_MSGQ_RECV GH_HYPERCALL(0x801C)
+#define GH_HYPERCALL_VCPU_RUN GH_HYPERCALL(0x8065)
/**
* gh_hypercall_hyp_identify() - Returns build information and feature flags
@@ -83,5 +84,32 @@ enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t
}
EXPORT_SYMBOL_GPL(gh_hypercall_msgq_recv);
+enum gh_error gh_hypercall_vcpu_run(u64 capid, u64 *resume_data,
+ struct gh_hypercall_vcpu_run_resp *resp)
+{
+ struct arm_smccc_1_2_regs args = {
+ .a0 = GH_HYPERCALL_VCPU_RUN,
+ .a1 = capid,
+ .a2 = resume_data[0],
+ .a3 = resume_data[1],
+ .a4 = resume_data[2],
+ /* C language says this will be implictly zero. Gunyah requires 0, so be explicit */
+ .a5 = 0,
+ };
+ struct arm_smccc_1_2_regs res;
+
+ arm_smccc_1_2_hvc(&args, &res);
+
+ if (res.a0 == GH_ERROR_OK) {
+ resp->sized_state = res.a1;
+ resp->state_data[0] = res.a2;
+ resp->state_data[1] = res.a3;
+ resp->state_data[2] = res.a4;
+ }
+
+ return res.a0;
+}
+EXPORT_SYMBOL_GPL(gh_hypercall_vcpu_run);
+
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("Gunyah Hypervisor Hypercalls");
diff --git a/drivers/virt/gunyah/Kconfig b/drivers/virt/gunyah/Kconfig
index 0421b751aad4..0a58395f7d2c 100644
--- a/drivers/virt/gunyah/Kconfig
+++ b/drivers/virt/gunyah/Kconfig
@@ -28,3 +28,14 @@ config GUNYAH_QCOM_PLATFORM
extra platform-specific support.
Say Y/M here to use Gunyah on Qualcomm platforms.
+
+config GUNYAH_VCPU
+ tristate "Runnable Gunyah vCPUs"
+ depends on GUNYAH
+ help
+ Enable kernel support for host-scheduled vCPUs running under Gunyah.
+ When selecting this option, userspace virtual machine managers (VMM)
+ can schedule the guest VM's vCPUs instead of using Gunyah's scheduler.
+ VMMs can also handle stage 2 faults of the vCPUs.
+
+ Say Y/M here if unsure and you want to support Gunyah VMMs.
diff --git a/drivers/virt/gunyah/Makefile b/drivers/virt/gunyah/Makefile
index 2aa9ff038ed0..cc16b6c19db9 100644
--- a/drivers/virt/gunyah/Makefile
+++ b/drivers/virt/gunyah/Makefile
@@ -5,3 +5,5 @@ obj-$(CONFIG_GUNYAH_QCOM_PLATFORM) += gunyah_qcom.o
gunyah-y += rsc_mgr.o rsc_mgr_rpc.o vm_mgr.o vm_mgr_mm.o
obj-$(CONFIG_GUNYAH) += gunyah.o
+
+obj-$(CONFIG_GUNYAH_VCPU) += gunyah_vcpu.o
diff --git a/drivers/virt/gunyah/gunyah_vcpu.c b/drivers/virt/gunyah/gunyah_vcpu.c
new file mode 100644
index 000000000000..4f0bbd58a205
--- /dev/null
+++ b/drivers/virt/gunyah/gunyah_vcpu.c
@@ -0,0 +1,468 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2022-2023 Qualcomm Innovation Center, Inc. All rights reserved.
+ */
+
+#include <linux/anon_inodes.h>
+#include <linux/file.h>
+#include <linux/gunyah.h>
+#include <linux/gunyah_vm_mgr.h>
+#include <linux/interrupt.h>
+#include <linux/kref.h>
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/wait.h>
+
+#include "vm_mgr.h"
+
+#include <uapi/linux/gunyah.h>
+
+#define MAX_VCPU_NAME 20 /* gh-vcpu:u32_max+NUL */
+
+struct gh_vcpu {
+ struct gh_vm_function_instance *f;
+ struct gh_resource *rsc;
+ struct mutex run_lock;
+ /* Track why vcpu_run left last time around. */
+ enum {
+ GH_VCPU_UNKNOWN = 0,
+ GH_VCPU_READY,
+ GH_VCPU_MMIO_READ,
+ GH_VCPU_SYSTEM_DOWN,
+ } state;
+ u8 mmio_read_len;
+ struct gh_vcpu_run *vcpu_run;
+ struct completion ready;
+ struct gh_vm *ghvm;
+
+ struct notifier_block nb;
+ struct gh_vm_resource_ticket ticket;
+ struct kref kref;
+};
+
+static void vcpu_release(struct kref *kref)
+{
+ struct gh_vcpu *vcpu = container_of(kref, struct gh_vcpu, kref);
+
+ free_page((unsigned long)vcpu->vcpu_run);
+ kfree(vcpu);
+}
+
+/*
+ * When hypervisor allows us to schedule vCPU again, it gives us an interrupt
+ */
+static irqreturn_t gh_vcpu_irq_handler(int irq, void *data)
+{
+ struct gh_vcpu *vcpu = data;
+
+ complete(&vcpu->ready);
+ return IRQ_HANDLED;
+}
+
+static bool gh_handle_mmio(struct gh_vcpu *vcpu,
+ struct gh_hypercall_vcpu_run_resp *vcpu_run_resp)
+{
+ int ret = 0;
+ u64 addr = vcpu_run_resp->state_data[0],
+ len = vcpu_run_resp->state_data[1],
+ data = vcpu_run_resp->state_data[2];
+
+ if (WARN_ON(len > sizeof(u64)))
+ len = sizeof(u64);
+
+ if (vcpu_run_resp->state == GH_VCPU_ADDRSPACE_VMMIO_READ) {
+ vcpu->vcpu_run->mmio.is_write = 0;
+ /* Record that we need to give vCPU user's supplied value next gh_vcpu_run() */
+ vcpu->state = GH_VCPU_MMIO_READ;
+ vcpu->mmio_read_len = len;
+ } else { /* GH_VCPU_ADDRSPACE_VMMIO_WRITE */
+ /* Try internal handlers first */
+ ret = gh_vm_mmio_write(vcpu->f->ghvm, addr, len, data);
+ if (!ret)
+ return true;
+
+ /* Give userspace the info */
+ vcpu->vcpu_run->mmio.is_write = 1;
+ memcpy(vcpu->vcpu_run->mmio.data, &data, len);
+ }
+
+ vcpu->vcpu_run->mmio.phys_addr = addr;
+ vcpu->vcpu_run->mmio.len = len;
+ vcpu->vcpu_run->exit_reason = GH_VCPU_EXIT_MMIO;
+
+ return false;
+}
+
+static int gh_vcpu_rm_notification(struct notifier_block *nb, unsigned long action, void *data)
+{
+ struct gh_vcpu *vcpu = container_of(nb, struct gh_vcpu, nb);
+ struct gh_rm_vm_exited_payload *exit_payload = data;
+
+ if (action == GH_RM_NOTIFICATION_VM_EXITED &&
+ le16_to_cpu(exit_payload->vmid) == vcpu->ghvm->vmid)
+ complete(&vcpu->ready);
+
+ return NOTIFY_OK;
+}
+
+static inline enum gh_vm_status remap_vm_status(enum gh_rm_vm_status rm_status)
+{
+ switch (rm_status) {
+ case GH_RM_VM_STATUS_INIT_FAILED:
+ return GH_VM_STATUS_LOAD_FAILED;
+ case GH_RM_VM_STATUS_EXITED:
+ return GH_VM_STATUS_EXITED;
+ default:
+ return GH_VM_STATUS_CRASHED;
+ }
+}
+
+/**
+ * gh_vcpu_check_system() - Check whether VM as a whole is running
+ * @vcpu: Pointer to gh_vcpu
+ *
+ * Returns true if the VM is alive.
+ * Returns false if the vCPU is the VM is not alive (can only be that VM is shutting down).
+ */
+static bool gh_vcpu_check_system(struct gh_vcpu *vcpu)
+ __must_hold(&vcpu->run_lock)
+{
+ bool ret = true;
+
+ down_read(&vcpu->ghvm->status_lock);
+ if (likely(vcpu->ghvm->vm_status == GH_RM_VM_STATUS_RUNNING))
+ goto out;
+
+ vcpu->vcpu_run->status.status = remap_vm_status(vcpu->ghvm->vm_status);
+ vcpu->vcpu_run->status.exit_info = vcpu->ghvm->exit_info;
+ vcpu->vcpu_run->exit_reason = GH_VCPU_EXIT_STATUS;
+ vcpu->state = GH_VCPU_SYSTEM_DOWN;
+ ret = false;
+out:
+ up_read(&vcpu->ghvm->status_lock);
+ return ret;
+}
+
+/**
+ * gh_vcpu_run() - Request Gunyah to begin scheduling this vCPU.
+ * @vcpu: The client descriptor that was obtained via gh_vcpu_alloc()
+ */
+static int gh_vcpu_run(struct gh_vcpu *vcpu)
+{
+ struct gh_hypercall_vcpu_run_resp vcpu_run_resp;
+ u64 state_data[3] = { 0 };
+ enum gh_error gh_error;
+ int ret = 0;
+
+ if (!vcpu->f)
+ return -ENODEV;
+
+ if (mutex_lock_interruptible(&vcpu->run_lock))
+ return -ERESTARTSYS;
+
+ if (!vcpu->rsc) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ switch (vcpu->state) {
+ case GH_VCPU_UNKNOWN:
+ if (vcpu->ghvm->vm_status != GH_RM_VM_STATUS_RUNNING) {
+ /* Check if VM is up. If VM is starting, will block until VM is fully up
+ * since that thread does down_write.
+ */
+ if (!gh_vcpu_check_system(vcpu))
+ goto out;
+ }
+ vcpu->state = GH_VCPU_READY;
+ break;
+ case GH_VCPU_MMIO_READ:
+ if (unlikely(vcpu->mmio_read_len > sizeof(state_data[0])))
+ vcpu->mmio_read_len = sizeof(state_data[0]);
+ memcpy(&state_data[0], vcpu->vcpu_run->mmio.data, vcpu->mmio_read_len);
+ vcpu->state = GH_VCPU_READY;
+ break;
+ case GH_VCPU_SYSTEM_DOWN:
+ goto out;
+ default:
+ break;
+ }
+
+ while (!ret && !signal_pending(current)) {
+ if (vcpu->vcpu_run->immediate_exit) {
+ ret = -EINTR;
+ goto out;
+ }
+
+ gh_error = gh_hypercall_vcpu_run(vcpu->rsc->capid, state_data, &vcpu_run_resp);
+ if (gh_error == GH_ERROR_OK) {
+ switch (vcpu_run_resp.state) {
+ case GH_VCPU_STATE_READY:
+ if (need_resched())
+ schedule();
+ break;
+ case GH_VCPU_STATE_POWERED_OFF:
+ /* vcpu might be off because the VM is shut down.
+ * If so, it won't ever run again: exit back to user
+ */
+ if (!gh_vcpu_check_system(vcpu))
+ goto out;
+ /* Otherwise, another vcpu will turn it on (e.g. by PSCI)
+ * and hyp sends an interrupt to wake Linux up.
+ */
+ fallthrough;
+ case GH_VCPU_STATE_EXPECTS_WAKEUP:
+ ret = wait_for_completion_interruptible(&vcpu->ready);
+ /* reinitialize completion before next hypercall. If we reinitialize
+ * after the hypercall, interrupt may have already come before
+ * re-initializing the completion and then end up waiting for
+ * event that already happened.
+ */
+ reinit_completion(&vcpu->ready);
+ /* Check system status again. Completion might've
+ * come from gh_vcpu_rm_notification
+ */
+ if (!ret && !gh_vcpu_check_system(vcpu))
+ goto out;
+ break;
+ case GH_VCPU_STATE_BLOCKED:
+ schedule();
+ break;
+ case GH_VCPU_ADDRSPACE_VMMIO_READ:
+ case GH_VCPU_ADDRSPACE_VMMIO_WRITE:
+ if (!gh_handle_mmio(vcpu, &vcpu_run_resp))
+ goto out;
+ break;
+ default:
+ pr_warn_ratelimited("Unknown vCPU state: %llx\n",
+ vcpu_run_resp.sized_state);
+ schedule();
+ break;
+ }
+ } else if (gh_error == GH_ERROR_RETRY) {
+ schedule();
+ } else {
+ ret = gh_error_remap(gh_error);
+ }
+ }
+
+out:
+ mutex_unlock(&vcpu->run_lock);
+
+ if (signal_pending(current))
+ return -ERESTARTSYS;
+
+ return ret;
+}
+
+static long gh_vcpu_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
+{
+ struct gh_vcpu *vcpu = filp->private_data;
+ long ret = -EINVAL;
+
+ switch (cmd) {
+ case GH_VCPU_RUN:
+ ret = gh_vcpu_run(vcpu);
+ break;
+ case GH_VCPU_MMAP_SIZE:
+ ret = PAGE_SIZE;
+ break;
+ default:
+ break;
+ }
+ return ret;
+}
+
+static int gh_vcpu_release(struct inode *inode, struct file *filp)
+{
+ struct gh_vcpu *vcpu = filp->private_data;
+
+ gh_vm_put(vcpu->ghvm);
+ kref_put(&vcpu->kref, vcpu_release);
+ return 0;
+}
+
+static vm_fault_t gh_vcpu_fault(struct vm_fault *vmf)
+{
+ struct gh_vcpu *vcpu = vmf->vma->vm_file->private_data;
+ struct page *page = NULL;
+
+ if (vmf->pgoff == 0)
+ page = virt_to_page(vcpu->vcpu_run);
+
+ get_page(page);
+ vmf->page = page;
+ return 0;
+}
+
+static const struct vm_operations_struct gh_vcpu_ops = {
+ .fault = gh_vcpu_fault,
+};
+
+static int gh_vcpu_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ vma->vm_ops = &gh_vcpu_ops;
+ return 0;
+}
+
+static const struct file_operations gh_vcpu_fops = {
+ .owner = THIS_MODULE,
+ .unlocked_ioctl = gh_vcpu_ioctl,
+ .release = gh_vcpu_release,
+ .llseek = noop_llseek,
+ .mmap = gh_vcpu_mmap,
+};
+
+static bool gh_vcpu_populate(struct gh_vm_resource_ticket *ticket, struct gh_resource *ghrsc)
+{
+ struct gh_vcpu *vcpu = container_of(ticket, struct gh_vcpu, ticket);
+ int ret;
+
+ mutex_lock(&vcpu->run_lock);
+ if (vcpu->rsc) {
+ pr_warn("vcpu%d already got a Gunyah resource. Check if multiple resources with same label were configured.\n",
+ vcpu->ticket.label);
+ ret = -EEXIST;
+ goto out;
+ }
+
+ vcpu->rsc = ghrsc;
+ init_completion(&vcpu->ready);
+
+ ret = request_irq(vcpu->rsc->irq, gh_vcpu_irq_handler, IRQF_TRIGGER_RISING, "gh_vcpu",
+ vcpu);
+ if (ret)
+ pr_warn("Failed to request vcpu irq %d: %d", vcpu->rsc->irq, ret);
+
+out:
+ mutex_unlock(&vcpu->run_lock);
+ return !ret;
+}
+
+static void gh_vcpu_unpopulate(struct gh_vm_resource_ticket *ticket,
+ struct gh_resource *ghrsc)
+{
+ struct gh_vcpu *vcpu = container_of(ticket, struct gh_vcpu, ticket);
+
+ vcpu->vcpu_run->immediate_exit = true;
+ complete_all(&vcpu->ready);
+ mutex_lock(&vcpu->run_lock);
+ free_irq(vcpu->rsc->irq, vcpu);
+ vcpu->rsc = NULL;
+ mutex_unlock(&vcpu->run_lock);
+}
+
+static long gh_vcpu_bind(struct gh_vm_function_instance *f)
+{
+ struct gh_fn_vcpu_arg *arg = f->argp;
+ struct gh_vcpu *vcpu;
+ char name[MAX_VCPU_NAME];
+ struct file *file;
+ struct page *page;
+ int fd;
+ long r;
+
+ if (f->arg_size != sizeof(*arg))
+ return -EINVAL;
+
+ vcpu = kzalloc(sizeof(*vcpu), GFP_KERNEL);
+ if (!vcpu)
+ return -ENOMEM;
+
+ vcpu->f = f;
+ f->data = vcpu;
+ mutex_init(&vcpu->run_lock);
+ kref_init(&vcpu->kref);
+
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page) {
+ r = -ENOMEM;
+ goto err_destroy_vcpu;
+ }
+ vcpu->vcpu_run = page_address(page);
+
+ vcpu->ticket.resource_type = GH_RESOURCE_TYPE_VCPU;
+ vcpu->ticket.label = arg->id;
+ vcpu->ticket.owner = THIS_MODULE;
+ vcpu->ticket.populate = gh_vcpu_populate;
+ vcpu->ticket.unpopulate = gh_vcpu_unpopulate;
+
+ r = gh_vm_add_resource_ticket(f->ghvm, &vcpu->ticket);
+ if (r)
+ goto err_destroy_page;
+
+ if (!gh_vm_get(f->ghvm)) {
+ r = -ENODEV;
+ goto err_remove_resource_ticket;
+ }
+ vcpu->ghvm = f->ghvm;
+
+ vcpu->nb.notifier_call = gh_vcpu_rm_notification;
+ /* Ensure we run after the vm_mgr handles the notification and does
+ * any necessary state changes. We wake up to check the new state.
+ */
+ vcpu->nb.priority = -1;
+ r = gh_rm_notifier_register(f->rm, &vcpu->nb);
+ if (r)
+ goto err_put_gh_vm;
+
+ kref_get(&vcpu->kref);
+
+ fd = get_unused_fd_flags(O_CLOEXEC);
+ if (fd < 0) {
+ r = fd;
+ goto err_notifier;
+ }
+
+ snprintf(name, sizeof(name), "gh-vcpu:%u", vcpu->ticket.label);
+ file = anon_inode_getfile(name, &gh_vcpu_fops, vcpu, O_RDWR);
+ if (IS_ERR(file)) {
+ r = PTR_ERR(file);
+ goto err_put_fd;
+ }
+
+ fd_install(fd, file);
+
+ return fd;
+err_put_fd:
+ put_unused_fd(fd);
+err_notifier:
+ gh_rm_notifier_unregister(f->rm, &vcpu->nb);
+err_put_gh_vm:
+ gh_vm_put(vcpu->ghvm);
+err_remove_resource_ticket:
+ gh_vm_remove_resource_ticket(f->ghvm, &vcpu->ticket);
+err_destroy_page:
+ free_page((unsigned long)vcpu->vcpu_run);
+err_destroy_vcpu:
+ kfree(vcpu);
+ return r;
+}
+
+static void gh_vcpu_unbind(struct gh_vm_function_instance *f)
+{
+ struct gh_vcpu *vcpu = f->data;
+
+ gh_rm_notifier_unregister(f->rm, &vcpu->nb);
+ gh_vm_remove_resource_ticket(vcpu->f->ghvm, &vcpu->ticket);
+ vcpu->f = NULL;
+
+ kref_put(&vcpu->kref, vcpu_release);
+}
+
+static bool gh_vcpu_compare(const struct gh_vm_function_instance *f,
+ const void *arg, size_t size)
+{
+ const struct gh_fn_vcpu_arg *instance = f->argp,
+ *other = arg;
+
+ if (sizeof(*other) != size)
+ return false;
+
+ return instance->id == other->id;
+}
+
+DECLARE_GH_VM_FUNCTION_INIT(vcpu, GH_FN_VCPU, 1, gh_vcpu_bind, gh_vcpu_unbind, gh_vcpu_compare);
+MODULE_DESCRIPTION("Gunyah vCPU Function");
+MODULE_LICENSE("GPL");
diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
index 81b42ab675f6..e7844204c151 100644
--- a/drivers/virt/gunyah/vm_mgr.c
+++ b/drivers/virt/gunyah/vm_mgr.c
@@ -408,6 +408,10 @@ static int gh_vm_rm_notification_exited(struct gh_vm *ghvm, void *data)
down_write(&ghvm->status_lock);
ghvm->vm_status = GH_RM_VM_STATUS_EXITED;
+ ghvm->exit_info.type = le16_to_cpu(payload->exit_type);
+ ghvm->exit_info.reason_size = le32_to_cpu(payload->exit_reason_size);
+ memcpy(&ghvm->exit_info.reason, payload->exit_reason,
+ min(GH_VM_MAX_EXIT_REASON_SIZE, ghvm->exit_info.reason_size));
up_write(&ghvm->status_lock);
wake_up(&ghvm->vm_status_wait);
diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
index 3fc0f91dfd1a..fa2a61e10b57 100644
--- a/drivers/virt/gunyah/vm_mgr.h
+++ b/drivers/virt/gunyah/vm_mgr.h
@@ -45,6 +45,7 @@ struct gh_vm {
enum gh_rm_vm_status vm_status;
wait_queue_head_t vm_status_wait;
struct rw_semaphore status_lock;
+ struct gh_vm_exit_info exit_info;
struct work_struct free_work;
struct kref kref;
diff --git a/include/linux/gunyah.h b/include/linux/gunyah.h
index 4b398b59c2c5..cd5704a82c6a 100644
--- a/include/linux/gunyah.h
+++ b/include/linux/gunyah.h
@@ -177,4 +177,28 @@ enum gh_error gh_hypercall_msgq_send(u64 capid, size_t size, void *buff, u64 tx_
enum gh_error gh_hypercall_msgq_recv(u64 capid, void *buff, size_t size, size_t *recv_size,
bool *ready);
+struct gh_hypercall_vcpu_run_resp {
+ union {
+ enum {
+ /* VCPU is ready to run */
+ GH_VCPU_STATE_READY = 0,
+ /* VCPU is sleeping until an interrupt arrives */
+ GH_VCPU_STATE_EXPECTS_WAKEUP = 1,
+ /* VCPU is powered off */
+ GH_VCPU_STATE_POWERED_OFF = 2,
+ /* VCPU is blocked in EL2 for unspecified reason */
+ GH_VCPU_STATE_BLOCKED = 3,
+ /* VCPU has returned for MMIO READ */
+ GH_VCPU_ADDRSPACE_VMMIO_READ = 4,
+ /* VCPU has returned for MMIO WRITE */
+ GH_VCPU_ADDRSPACE_VMMIO_WRITE = 5,
+ } state;
+ u64 sized_state;
+ };
+ u64 state_data[3];
+};
+
+enum gh_error gh_hypercall_vcpu_run(u64 capid, u64 *resume_data,
+ struct gh_hypercall_vcpu_run_resp *resp);
+
#endif
diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
index bb07118a351f..434ffa8ffc78 100644
--- a/include/uapi/linux/gunyah.h
+++ b/include/uapi/linux/gunyah.h
@@ -72,8 +72,33 @@ struct gh_vm_dtb_config {
#define GH_VM_START _IO(GH_IOCTL_TYPE, 0x3)
+/**
+ * enum gh_fn_type - Valid types of Gunyah VM functions
+ * @GH_FN_VCPU: create a vCPU instance to control a vCPU
+ * &struct gh_fn_desc.arg is a pointer to &struct gh_fn_vcpu_arg
+ * Return: file descriptor to manipulate the vcpu.
+ */
+enum gh_fn_type {
+ GH_FN_VCPU = 1,
+};
+
#define GH_FN_MAX_ARG_SIZE 256
+/**
+ * struct gh_fn_vcpu_arg - Arguments to create a vCPU.
+ * @id: vcpu id
+ *
+ * Create this function with &GH_VM_ADD_FUNCTION using type &GH_FN_VCPU.
+ *
+ * The vcpu type will register with the VM Manager to expect to control
+ * vCPU number `vcpu_id`. It returns a file descriptor allowing interaction with
+ * the vCPU. See the Gunyah vCPU API description sections for interacting with
+ * the Gunyah vCPU file descriptors.
+ */
+struct gh_fn_vcpu_arg {
+ __u32 id;
+};
+
/**
* struct gh_fn_desc - Arguments to create a VM function
* @type: Type of the function. See &enum gh_fn_type.
@@ -90,4 +115,107 @@ struct gh_fn_desc {
#define GH_VM_ADD_FUNCTION _IOW(GH_IOCTL_TYPE, 0x4, struct gh_fn_desc)
#define GH_VM_REMOVE_FUNCTION _IOW(GH_IOCTL_TYPE, 0x7, struct gh_fn_desc)
+/*
+ * ioctls for vCPU fds
+ */
+
+/**
+ * enum gh_vm_status - Stores status reason why VM is not runnable (exited).
+ * @GH_VM_STATUS_LOAD_FAILED: VM didn't start because it couldn't be loaded.
+ * @GH_VM_STATUS_EXITED: VM requested shutdown/reboot.
+ * Use &struct gh_vm_exit_info.reason for further details.
+ * @GH_VM_STATUS_CRASHED: VM state is unknown and has crashed.
+ */
+enum gh_vm_status {
+ GH_VM_STATUS_LOAD_FAILED = 1,
+ GH_VM_STATUS_EXITED = 2,
+ GH_VM_STATUS_CRASHED = 3,
+};
+
+/*
+ * Gunyah presently sends max 4 bytes of exit_reason.
+ * If that changes, this macro can be safely increased without breaking
+ * userspace so long as struct gh_vcpu_run < PAGE_SIZE.
+ */
+#define GH_VM_MAX_EXIT_REASON_SIZE 8u
+
+/**
+ * struct gh_vm_exit_info - Reason for VM exit as reported by Gunyah
+ * See Gunyah documentation for values.
+ * @type: Describes how VM exited
+ * @padding: padding bytes
+ * @reason_size: Number of bytes valid for `reason`
+ * @reason: See Gunyah documentation for interpretation. Note: these values are
+ * not interpreted by Linux and need to be converted from little-endian
+ * as applicable.
+ */
+struct gh_vm_exit_info {
+ __u16 type;
+ __u16 padding;
+ __u32 reason_size;
+ __u8 reason[GH_VM_MAX_EXIT_REASON_SIZE];
+};
+
+/**
+ * enum gh_vcpu_exit - Stores reason why &GH_VCPU_RUN ioctl recently exited with status 0
+ * @GH_VCPU_EXIT_UNKNOWN: Not used, status != 0
+ * @GH_VCPU_EXIT_MMIO: vCPU performed a read or write that could not be handled
+ * by hypervisor or Linux. Use @struct gh_vcpu_run.mmio for
+ * details of the read/write.
+ * @GH_VCPU_EXIT_STATUS: vCPU not able to run because the VM has exited.
+ * Use @struct gh_vcpu_run.status for why VM has exited.
+ */
+enum gh_vcpu_exit {
+ GH_VCPU_EXIT_UNKNOWN,
+ GH_VCPU_EXIT_MMIO,
+ GH_VCPU_EXIT_STATUS,
+};
+
+/**
+ * struct gh_vcpu_run - Application code obtains a pointer to the gh_vcpu_run
+ * structure by mmap()ing a vcpu fd.
+ * @immediate_exit: polled when scheduling the vcpu. If set, immediately returns -EINTR.
+ * @padding: padding bytes
+ * @exit_reason: Set when GH_VCPU_RUN returns successfully and gives reason why
+ * GH_VCPU_RUN has stopped running the vCPU. See &enum gh_vcpu_exit.
+ * @mmio: Used when exit_reason == GH_VCPU_EXIT_MMIO
+ * The guest has faulted on an memory-mapped I/O instruction that
+ * couldn't be satisfied by gunyah.
+ * @mmio.phys_addr: Address guest tried to access
+ * @mmio.data: the value that was written if `is_write == 1`. Filled by
+ * user for reads (`is_write == 0`).
+ * @mmio.len: Length of write. Only the first `len` bytes of `data`
+ * are considered by Gunyah.
+ * @mmio.is_write: 1 if VM tried to perform a write, 0 for a read
+ * @status: Used when exit_reason == GH_VCPU_EXIT_STATUS.
+ * The guest VM is no longer runnable. This struct informs why.
+ * @status.status: See &enum gh_vm_status for possible values
+ * @status.exit_info: Used when status == GH_VM_STATUS_EXITED
+ */
+struct gh_vcpu_run {
+ /* in */
+ __u8 immediate_exit;
+ __u8 padding[7];
+
+ /* out */
+ __u32 exit_reason;
+
+ union {
+ struct {
+ __u64 phys_addr;
+ __u8 data[8];
+ __u32 len;
+ __u8 is_write;
+ } mmio;
+
+ struct {
+ enum gh_vm_status status;
+ struct gh_vm_exit_info exit_info;
+ } status;
+ };
+};
+
+#define GH_VCPU_RUN _IO(GH_IOCTL_TYPE, 0x5)
+#define GH_VCPU_MMAP_SIZE _IO(GH_IOCTL_TYPE, 0x6)
+
#endif
--
2.40.0
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