From f561ba5b22b8697f6f28761c36d74811bc70ccc3 Mon Sep 17 00:00:00 2001 From: Elliot Berman Date: Thu, 22 Feb 2024 15:16:53 -0800 Subject: [PATCH] FROMLIST: virt: gunyah: Allow userspace to initialize context of primary vCPU RM provides APIs to fill boot context the initial registers upon starting the vCPU. Most importantly, this allows userspace to set the initial PC for the primary vCPU when the VM starts to run. Bug: 338347082 Link: https://lore.kernel.org/all/20240222-gunyah-v17-30-1e9da6763d38@quicinc.com/ Change-Id: Ieadc38f0cbe4a723bca488f47812cf130a039ca5 Signed-off-by: Elliot Berman Signed-off-by: Elliot Berman --- drivers/virt/gunyah/vm_mgr.c | 77 ++++++++++++++++++++++++++++++++++++ drivers/virt/gunyah/vm_mgr.h | 2 + include/uapi/linux/gunyah.h | 23 +++++++++++ 3 files changed, 102 insertions(+) diff --git a/drivers/virt/gunyah/vm_mgr.c b/drivers/virt/gunyah/vm_mgr.c index 473740a1f97d..a61a3f3ae92f 100644 --- a/drivers/virt/gunyah/vm_mgr.c +++ b/drivers/virt/gunyah/vm_mgr.c @@ -402,6 +402,7 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm) mutex_init(&ghvm->resources_lock); INIT_LIST_HEAD(&ghvm->resources); INIT_LIST_HEAD(&ghvm->resource_tickets); + xa_init(&ghvm->boot_context); mt_init(&ghvm->mm); mt_init(&ghvm->bindings); @@ -427,6 +428,66 @@ static __must_check struct gunyah_vm *gunyah_vm_alloc(struct gunyah_rm *rm) return ghvm; } +static long gunyah_vm_set_boot_context(struct gunyah_vm *ghvm, + struct gunyah_vm_boot_context *boot_ctx) +{ + u8 reg_set, reg_index; /* to check values are reasonable */ + int ret; + + reg_set = (boot_ctx->reg >> GUNYAH_VM_BOOT_CONTEXT_REG_SHIFT) & 0xff; + reg_index = boot_ctx->reg & 0xff; + + switch (reg_set) { + case REG_SET_X: + if (reg_index > 31) + return -EINVAL; + break; + case REG_SET_PC: + if (reg_index) + return -EINVAL; + break; + case REG_SET_SP: + if (reg_index > 2) + return -EINVAL; + break; + default: + return -EINVAL; + } + + ret = down_read_interruptible(&ghvm->status_lock); + if (ret) + return ret; + + if (ghvm->vm_status != GUNYAH_RM_VM_STATUS_NO_STATE) { + ret = -EINVAL; + goto out; + } + + ret = xa_err(xa_store(&ghvm->boot_context, boot_ctx->reg, + (void *)boot_ctx->value, GFP_KERNEL)); +out: + up_read(&ghvm->status_lock); + return ret; +} + +static inline int gunyah_vm_fill_boot_context(struct gunyah_vm *ghvm) +{ + unsigned long reg_set, reg_index, id; + void *entry; + int ret; + + xa_for_each(&ghvm->boot_context, id, entry) { + reg_set = (id >> GUNYAH_VM_BOOT_CONTEXT_REG_SHIFT) & 0xff; + reg_index = id & 0xff; + ret = gunyah_rm_vm_set_boot_context( + ghvm->rm, ghvm->vmid, reg_set, reg_index, (u64)entry); + if (ret) + return ret; + } + + return 0; +} + static int gunyah_vm_start(struct gunyah_vm *ghvm) { struct gunyah_rm_hyp_resources *resources; @@ -499,6 +560,13 @@ static int gunyah_vm_start(struct gunyah_vm *ghvm) } ghvm->vm_status = GUNYAH_RM_VM_STATUS_READY; + ret = gunyah_vm_fill_boot_context(ghvm); + if (ret) { + dev_warn(ghvm->parent, "Failed to setup boot context: %d\n", + ret); + goto err; + } + ret = gunyah_rm_get_hyp_resources(ghvm->rm, ghvm->vmid, &resources); if (ret) { dev_warn(ghvm->parent, @@ -625,6 +693,14 @@ static long gunyah_vm_ioctl(struct file *filp, unsigned int cmd, return gunyah_gmem_modify_mapping(ghvm, &args); } + case GUNYAH_VM_SET_BOOT_CONTEXT: { + struct gunyah_vm_boot_context boot_ctx; + + if (copy_from_user(&boot_ctx, argp, sizeof(boot_ctx))) + return -EFAULT; + + return gunyah_vm_set_boot_context(ghvm, &boot_ctx); + } default: r = -ENOTTY; break; @@ -716,6 +792,7 @@ static void _gunyah_vm_put(struct kref *kref) "Failed to deallocate vmid: %d\n", ret); } + xa_destroy(&ghvm->boot_context); gunyah_rm_put(ghvm->rm); kfree(ghvm); } diff --git a/drivers/virt/gunyah/vm_mgr.h b/drivers/virt/gunyah/vm_mgr.h index 5eb14f30ba96..8cee93e55170 100644 --- a/drivers/virt/gunyah/vm_mgr.h +++ b/drivers/virt/gunyah/vm_mgr.h @@ -81,6 +81,7 @@ long gunyah_dev_vm_mgr_ioctl(struct gunyah_rm *rm, unsigned int cmd, * folio; parcel_start is start of the folio) * @dtb.parcel_pages: Number of pages lent for the memory parcel * @dtb.parcel: Data for resource manager to lend the parcel + * @boot_context: Requested initial boot context to set when launching the VM * * Members are grouped by hot path. */ @@ -115,6 +116,7 @@ struct gunyah_vm { u64 parcel_start, parcel_pages; struct gunyah_rm_mem_parcel parcel; } dtb; + struct xarray boot_context; }; /** diff --git a/include/uapi/linux/gunyah.h b/include/uapi/linux/gunyah.h index a89d9bedf3e5..574116f54472 100644 --- a/include/uapi/linux/gunyah.h +++ b/include/uapi/linux/gunyah.h @@ -142,6 +142,29 @@ struct gunyah_map_mem_args { #define GUNYAH_VM_MAP_MEM _IOW(GUNYAH_IOCTL_TYPE, 0x9, struct gunyah_map_mem_args) +enum gunyah_vm_boot_context_reg { + REG_SET_X = 0, + REG_SET_PC = 1, + REG_SET_SP = 2, +}; + +#define GUNYAH_VM_BOOT_CONTEXT_REG_SHIFT 8 +#define GUNYAH_VM_BOOT_CONTEXT_REG(reg, idx) (((reg & 0xff) << GUNYAH_VM_BOOT_CONTEXT_REG_SHIFT) |\ + (idx & 0xff)) + +/** + * struct gunyah_vm_boot_context - Set an initial register for the VM + * @reg: Register to set. See GUNYAH_VM_BOOT_CONTEXT_REG_* macros + * @reserved: reserved for alignment + * @value: value to fill in the register + */ +struct gunyah_vm_boot_context { + __u32 reg; + __u32 reserved; + __u64 value; +}; +#define GUNYAH_VM_SET_BOOT_CONTEXT _IOW(GUNYAH_IOCTL_TYPE, 0xa, struct gunyah_vm_boot_context) + /* * ioctls for vCPU fds */