diff options
Diffstat (limited to 'kernel/gsp_phys_booter.c')
| -rw-r--r-- | kernel/gsp_phys_booter.c | 99 |
1 files changed, 99 insertions, 0 deletions
diff --git a/kernel/gsp_phys_booter.c b/kernel/gsp_phys_booter.c index 4125192..b2375a2 100644 --- a/kernel/gsp_phys_booter.c +++ b/kernel/gsp_phys_booter.c @@ -25303,6 +25303,91 @@ static const struct file_operations gsp_phys_guest_gpa_fops = { }; /* + * gsp-phys-shared-bit0 (write-only, mode 0200): development-harness assist + * for the NVIDIA X driver's per-client shared-data slot. + * + * Every direct GLX client receives a shared memory page from the X driver + * (nvidia_drv.so creates a memfd and passes it over a unix socket) whose + * first words are {u32 zero, u32 cookie, u32 state, u32 zero, u32 hClient, + * u32 hObject}; glcore's device init reads the state word and skips its own + * class-c46f channel creation while bit 0 of it is set. In this emulated + * environment the X driver publishes state=3 (bits 0+1) and direct clients + * therefore never allocate a channel and never render. The value is written + * by the X driver before the fd reaches the client, so it cannot be + * corrected from the client side. + * + * Input: "0x<hex GPA>" (4 KB aligned) naming the guest page that carries the + * slot. The GPA must fall inside a range registered through + * gsp-phys-guest-ram; it is translated with gsp_phys_gpa_to_hpa_vgpu() + * (first open mdev) and the state word is cleared of bit 0 through the + * kernel direct map (the translator validates pfn_valid, so __va() is a + * valid kernel mapping for the shmem-backed guest RAM). As a sanity guard + * the write is only performed when the page's +0x10 word looks like an RM + * client handle (0xc1d0xxxx / 0xc1e0xxxx) or the token carries a "force" + * suffix. Old and new values are always logged. + * + * This is a diagnostic aid for the development VM, matching the spirit of + * the existing guest-GPA pin; it is not part of the product behaviour. + */ +static ssize_t gsp_phys_shared_bit0_write(struct file *file, + const char __user *ubuf, size_t len, + loff_t *ppos) +{ + char buf[48]; + u64 gpa, hpa = 0; + u32 *word; + u32 h1032; + bool force = false; + int ret; + + if (len == 0 || len >= sizeof(buf)) + return -EINVAL; + if (copy_from_user(buf, ubuf, len)) + return -EFAULT; + buf[len] = '\0'; + + { + char *p = strim(buf); + char *tok = strsep(&p, " \t"); + + if (p && strstr(p, "force")) + force = true; + if (kstrtoull(tok, 0, &gpa) || !PAGE_ALIGNED(gpa)) { + pr_info("vgsp-boot: gsp-phys-shared-bit0: write ignored: expected \"0x<hex GPA>\" (4 KB aligned, optional 'force')\n"); + return -EINVAL; + } + } + + ret = gsp_phys_gpa_to_hpa_vgpu(NULL, gpa, &hpa); + if (ret) { + pr_err("vgsp-boot: gsp-phys-shared-bit0: GPA 0x%llx translation failed (%d: no open mdev / GPA not inside a gsp-phys-guest-ram range / not RAM)\n", + gpa, ret); + return -ENOENT; + } + + word = (u32 *)__va(hpa + 8); + h1032 = *(u32 *)__va(hpa + 0x10); + if (!force && (h1032 >> 16) != 0xc1d0 && (h1032 >> 16) != 0xc1e0) { + pr_info("vgsp-boot: gsp-phys-shared-bit0: gpa=0x%llx word=0x%x but +0x10=0x%x does not look like an RM client handle; refusing (append 'force' to override)\n", + gpa, *word, h1032); + return -EINVAL; + } + + pr_info("vgsp-boot: gsp-phys-shared-bit0: gpa=0x%llx hpa=0x%llx hClient=0x%x word=0x%x -> 0x%x\n", + gpa, hpa, h1032, *word, *word & ~1u); + *word &= ~1u; + return len; +} + +static const struct file_operations gsp_phys_shared_bit0_fops = { + .owner = THIS_MODULE, + .open = simple_open, + .write = gsp_phys_shared_bit0_write, + .llseek = no_llseek, +}; + + +/* * gsp-phys-guest-ram (write-only, mode 0200): configure a guest RAM backing * file that gsp_phys_gpa_to_hpa_vgpu() translates through (QEMU * memory-backend-file,...,share=yes). One write is @@ -25787,6 +25872,20 @@ int gsp_phys_boot_debugfs_init(void) err); return (int)err; } + file = debugfs_create_file("gsp-phys-shared-bit0", 0200, + gsp_phys_debugfs_root, NULL, + &gsp_phys_shared_bit0_fops); + if (IS_ERR_OR_NULL(file)) { + long err = IS_ERR(file) ? PTR_ERR(file) : -ENODEV; + + /* + * The shared-slot bit0 assist is optional; the other + * triggers and the state snapshot stay registered. + */ + pr_warn("vgsp-boot: debugfs file gsp-phys-shared-bit0 creation failed: %ld (other triggers and state snapshot stay available)\n", + err); + return (int)err; + } file = debugfs_create_file("gsp-phys-guest-ram", 0200, gsp_phys_debugfs_root, NULL, &gsp_phys_guest_ram_fops); |