diff options
Diffstat (limited to 'arch/x86/virt/vmx/tdx/tdx.c')
-rw-r--r-- | arch/x86/virt/vmx/tdx/tdx.c | 81 |
1 files changed, 81 insertions, 0 deletions
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c new file mode 100644 index 000000000000..94689aef44a6 --- /dev/null +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright(c) 2023 Intel Corporation. + * + * Intel Trusted Domain Extensions (TDX) support + */ + +#define pr_fmt(fmt) "virt/tdx: " fmt + +#include <linux/types.h> +#include <linux/cache.h> +#include <linux/init.h> +#include <linux/errno.h> +#include <linux/printk.h> +#include <asm/msr-index.h> +#include <asm/msr.h> +#include <asm/cpufeature.h> +#include <asm/tdx.h> + +static u32 tdx_global_keyid __ro_after_init; +static u32 tdx_guest_keyid_start __ro_after_init; +static u32 tdx_nr_guest_keyids __ro_after_init; + +static __init int record_keyid_partitioning(u32 *tdx_keyid_start, + u32 *nr_tdx_keyids) +{ + u32 _nr_mktme_keyids, _tdx_keyid_start, _nr_tdx_keyids; + int ret; + + /* + * IA32_MKTME_KEYID_PARTIONING: + * Bit [31:0]: Number of MKTME KeyIDs. + * Bit [63:32]: Number of TDX private KeyIDs. + */ + ret = rdmsr_safe(MSR_IA32_MKTME_KEYID_PARTITIONING, &_nr_mktme_keyids, + &_nr_tdx_keyids); + if (ret || !_nr_tdx_keyids) + return -EINVAL; + + /* TDX KeyIDs start after the last MKTME KeyID. */ + _tdx_keyid_start = _nr_mktme_keyids + 1; + + *tdx_keyid_start = _tdx_keyid_start; + *nr_tdx_keyids = _nr_tdx_keyids; + + return 0; +} + +void __init tdx_init(void) +{ + u32 tdx_keyid_start, nr_tdx_keyids; + int err; + + err = record_keyid_partitioning(&tdx_keyid_start, &nr_tdx_keyids); + if (err) + return; + + pr_info("BIOS enabled: private KeyID range [%u, %u)\n", + tdx_keyid_start, tdx_keyid_start + nr_tdx_keyids); + + /* + * The TDX module itself requires one 'global KeyID' to protect + * its metadata. If there's only one TDX KeyID, there won't be + * any left for TDX guests thus there's no point to enable TDX + * at all. + */ + if (nr_tdx_keyids < 2) { + pr_err("initialization failed: too few private KeyIDs available.\n"); + return; + } + + /* + * Just use the first TDX KeyID as the 'global KeyID' and + * leave the rest for TDX guests. + */ + tdx_global_keyid = tdx_keyid_start; + tdx_guest_keyid_start = tdx_keyid_start + 1; + tdx_nr_guest_keyids = nr_tdx_keyids - 1; + + setup_force_cpu_cap(X86_FEATURE_TDX_HOST_PLATFORM); +} |