Re: [PATCH v9 14/27] gunyah: vm_mgr: Add ioctls to support basic non-proxy VM boot

Srinivas Kandagatla
2023-02-07T11:37:19Z

On 20/01/2023 22:46, Elliot Berman wrote:
> Add remaining ioctls to support non-proxy VM boot:
>
> - Gunyah Resource Manager uses the VM's devicetree to configure the
> virtual machine. The location of the devicetree in the guest's
> virtual memory can be declared via the SET_DTB_CONFIG ioctl.
> - Trigger start of the virtual machine with VM_START ioctl.
>
> Co-developed-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Prakruthi Deepak Heragu <quic_pheragu@quicinc.com>
> Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
> ---
> drivers/virt/gunyah/vm_mgr.c | 110 ++++++++++++++++++++++++++++++++
> drivers/virt/gunyah/vm_mgr.h | 9 +++
> drivers/virt/gunyah/vm_mgr_mm.c | 24 +++++++
> include/uapi/linux/gunyah.h | 8 +++
> 4 files changed, 151 insertions(+)
>
> diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c
> index b847fde63333..48bd3f06fb6c 100644
> --- a/drivers/virt/gunyah/vm_mgr.c
> +++ b/drivers/virt/gunyah/vm_mgr.c
> @@ -9,6 +9,7 @@
> #include <linux/file.h>
> #include <linux/gunyah_rsc_mgr.h>
> #include <linux/miscdevice.h>
> +#include <linux/mm.h>
> #include <linux/module.h>
>
> #include <uapi/linux/gunyah.h>
> @@ -37,10 +38,98 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gh_rm_rpc *rm)
>
> mutex_init(&ghvm->mm_lock);
> INIT_LIST_HEAD(&ghvm->memory_mappings);
> + init_rwsem(&ghvm->status_lock);
>

using read write semaphore is really not going to make any difference in
this particular case.
we have just one reader (gh_vm_ensure_started) and it mostly makes
synchronous call to writer (vm_start).

> return ghvm;
> }
>
> +static int gh_vm_start(struct gunyah_vm *ghvm)
> +{
> + struct gunyah_vm_memory_mapping *mapping;
> + u64 dtb_offset;
> + u32 mem_handle;
> + int ret;
> +
> + down_write(&ghvm->status_lock);
> + if (ghvm->vm_status != GH_RM_VM_STATUS_NO_STATE) {
> + up_write(&ghvm->status_lock);
> + return 0;
> + }
> +
> + list_for_each_entry(mapping, &ghvm->memory_mappings, list) {
> + switch (mapping->share_type) {
> + case VM_MEM_LEND:
> + ret = gh_rm_mem_lend(ghvm->rm, &mapping->parcel);
> + break;
> + case VM_MEM_SHARE:
> + ret = gh_rm_mem_share(ghvm->rm, &mapping->parcel);
> + break;
> + }

> + if (ret > 0)
> + ret = -EINVAL;

why are we converting the error messages, afaiu both gh_rm_mem_lend and
gh_rm_mem_share return a valid error codes.

> + if (ret) {
> + pr_warn("Failed to %s parcel %d: %d\n",
> + mapping->share_type == VM_MEM_LEND ? "lend" : "share",
> + mapping->parcel.label,
> + ret);
> + goto err;
> + }
> + }
> +
> + mapping = gh_vm_mem_mapping_find_mapping(ghvm, ghvm->dtb_config.gpa, ghvm->dtb_config.size);
> + if (!mapping) {
> + pr_warn("Failed to find the memory_handle for DTB\n");
> + ret = -EINVAL;
> + goto err;
> + }
> +
> + mem_handle = mapping->parcel.mem_handle;
> + dtb_offset = ghvm->dtb_config.gpa - mapping->guest_phys_addr;
> +
> + ret = gh_rm_vm_configure(ghvm->rm, ghvm->vmid, ghvm->auth, mem_handle,
> + 0, 0, dtb_offset, ghvm->dtb_config.size);
> + if (ret) {
> + pr_warn("Failed to configure VM: %d\n", ret);
> + goto err;
> + }
> +
> + ret = gh_rm_vm_init(ghvm->rm, ghvm->vmid);
> + if (ret) {
> + pr_warn("Failed to initialize VM: %d\n", ret);
> + goto err;
> + }
> +
> + ret = gh_rm_vm_start(ghvm->rm, ghvm->vmid);
> + if (ret) {
> + pr_warn("Failed to start VM: %d\n", ret);
> + goto err;
> + }
> +
> + ghvm->vm_status = GH_RM_VM_STATUS_READY;
> +
> + up_write(&ghvm->stvm_status = atus_lock);
> + return ret;
> +err:
> + ghvm->vm_status = GH_RM_VM_STATUS_INIT_FAILED;
> + up_write(&ghvm->status_lock);
> + return ret;
> +}
> +
> +static void gh_vm_stop(struct gunyah_vm *ghvm)
> +{
> + int ret;
> +
> + down_write(&ghvm->status_lock);
> + if (ghvm->vm_status == GH_RM_VM_STATUS_READY) {
> + ret = gh_rm_vm_stop(ghvm->rm, ghvm->vmid);
> + if (ret)
> + pr_warn("Failed to stop VM: %d\n", ret);
> + }
> +
> + ghvm->vm_status = GH_RM_VM_STATUS_EXITED;
> + up_write(&ghvm->status_lock);
> +}
> +
> static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> {
> struct gunyah_vm *ghvm = filp->private_data;
> @@ -84,6 +173,25 @@ static long gh_vm_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
> }
> break;
> }
> + case GH_VM_SET_DTB_CONFIG: {
> + struct gh_vm_dtb_config dtb_config;
> +
> + r = -EFAULT;
> + if (copy_from_user(&dtb_config, argp, sizeof(dtb_config)))
> + break;
> +
same feedback as other patches on setting error codes.
> + dtb_config.size = PAGE_ALIGN(dtb_config.size);
> + ghvm->dtb_config = dtb_config;
> +
> + r = 0;
> + break;
> + }
> + case GH_VM_START: {
> + r = gh_vm_start(ghvm);
> + if (r)
> + r = -EINVAL;
> + break;
> + }
> default:
> r = -ENOTTY;
> break;
> @@ -97,6 +205,8 @@ static int gh_vm_release(struct inode *inode, struct file *filp)
> struct gunyah_vm *ghvm = filp->private_data;
> struct gunyah_vm_memory_mapping *mapping, *tmp;
>
> + gh_vm_stop(ghvm);
> +
> list_for_each_entry_safe(mapping, tmp, &ghvm->memory_mappings, list) {
> gh_vm_mem_mapping_reclaim(ghvm, mapping);
> kfree(mapping);
> diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h
> index 6b38bf780f76..5c02fb305893 100644
> --- a/drivers/virt/gunyah/vm_mgr.h
> +++ b/drivers/virt/gunyah/vm_mgr.h
> @@ -10,6 +10,7 @@
> #include <linux/list.h>
> #include <linux/miscdevice.h>
> #include <linux/mutex.h>
> +#include <linux/rwsem.h>
>
> #include <uapi/linux/gunyah.h>
>
> @@ -34,6 +35,12 @@ struct gunyah_vm {
> u16 vmid;
> struct gh_rm *rm;
>
> + enum gh_rm_vm_auth_mechanism auth;
> + struct gh_vm_dtb_config dtb_config;
> +
> + enum gh_rm_vm_status vm_status;
> + struct rw_semaphore status_lock;
> +
> struct mutex mm_lock;
> struct list_head memory_mappings;
> };
> @@ -42,5 +49,7 @@ struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_alloc(struct gunyah_vm *ghvm,
> struct gh_userspace_memory_region *region);
> void gh_vm_mem_mapping_reclaim(struct gunyah_vm *ghvm, struct gunyah_vm_memory_mapping *mapping);
> struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find(struct gunyah_vm *ghvm, u32 label);
> +struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find_mapping(struct gunyah_vm *ghvm,
> + u64 gpa, u32 size);
>
> #endif
> diff --git a/drivers/virt/gunyah/vm_mgr_mm.c b/drivers/virt/gunyah/vm_mgr_mm.c
> index f2dbdb4ee8ab..7fcb9f8a29bf 100644
> --- a/drivers/virt/gunyah/vm_mgr_mm.c
> +++ b/drivers/virt/gunyah/vm_mgr_mm.c
> @@ -53,6 +53,30 @@ void gh_vm_mem_mapping_reclaim(struct gunyah_vm *ghvm, struct gunyah_vm_memory_m
> mutex_unlock(&ghvm->mm_lock);
> }
>
> +struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find_mapping(struct gunyah_vm *ghvm,
> + u64 gpa, u32 size)
> +{
> + struct gunyah_vm_memory_mapping *mapping = NULL;
> + int ret;
> +
> + ret = mutex_lock_interruptible(&ghvm->mm_lock);
> + if (ret)
> + return ERR_PTR(ret);
> +
> + list_for_each_entry(mapping, &ghvm->memory_mappings, list) {
> + if (gpa >= mapping->guest_phys_addr &&
> + (gpa + size <= mapping->guest_phys_addr +
> + (mapping->npages << PAGE_SHIFT))) {
> + goto unlock;
> + }
> + }
> +
> + mapping = NULL;
> +unlock:
> + mutex_unlock(&ghvm->mm_lock);
> + return mapping;
> +}
> +
> struct gunyah_vm_memory_mapping *gh_vm_mem_mapping_find(struct gunyah_vm *ghvm, u32 label)
> {
> struct gunyah_vm_memory_mapping *mapping;
> diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h
> index 574f33b198d0..36359ad2175e 100644
> --- a/include/uapi/linux/gunyah.h
> +++ b/include/uapi/linux/gunyah.h
> @@ -42,4 +42,12 @@ struct gh_userspace_memory_region {
> #define GH_VM_SET_USER_MEM_REGION _IOW(GH_IOCTL_TYPE, 0x1, \
> struct gh_userspace_memory_region)
>
> +struct gh_vm_dtb_config {
> + __u64 gpa;

need kernedoc, what is gpa?

> + __u64 size;
> +};
> +#define GH_VM_SET_DTB_CONFIG _IOW(GH_IOCTL_TYPE, 0x2, struct gh_vm_dtb_config)
> +
> +#define GH_VM_START _IO(GH_IOCTL_TYPE, 0x3)
> +
> #endif