The TDG_VM_WR TDCALL is used to ask the TDX module to change some TD-specific VM configuration. There is currently only one user in the kernel of this TDCALL leaf. More will be added shortly.

Refactor to make way for more users of TDG_VM_WR who will need to modify other TD configuration values.

Add a wrapper for the TDG_VM_RD TDCALL that requests TD-specific metadata from the TDX module. There are currently no users for TDG_VM_RD. Mark it as __maybe_unused until the first user appears.

This is preparation for enumeration and enabling optional TD features.

Signed-off-by: Kirill A. Shutemov kirill.shutemov@linux.intel.com Reviewed-by: Kai Huang kai.huang@intel.com Reviewed-by: Kuppuswamy Sathyanarayanan sathyanarayanan.kuppuswamy@linux.intel.com Cc: stable@vger.kernel.org --- arch/x86/coco/tdx/tdx.c | 32 ++++++++++++++++++++++++++----- arch/x86/include/asm/shared/tdx.h | 1 + 2 files changed, 28 insertions(+), 5 deletions(-)

diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 327c45c5013f..c74bb9e7d7a3 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -78,6 +78,32 @@ static inline void tdcall(u64 fn, struct tdx_module_args *args) panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); }

+/* Read TD-scoped metadata */ +static inline u64 __maybe_unused tdg_vm_rd(u64 field, u64 *value) +{ + struct tdx_module_args args = { + .rdx = field, + }; + u64 ret; + + ret = __tdcall_ret(TDG_VM_RD, &args); + *value = args.r8; + + return ret; +} + +/* Write TD-scoped metadata */ +static inline u64 tdg_vm_wr(u64 field, u64 value, u64 mask) +{ + struct tdx_module_args args = { + .rdx = field, + .r8 = value, + .r9 = mask, + }; + + return __tdcall(TDG_VM_WR, &args); +} + /** * tdx_mcall_get_report0() - Wrapper to get TDREPORT0 (a.k.a. TDREPORT * subtype 0) using TDG.MR.REPORT TDCALL. @@ -929,10 +955,6 @@ static void tdx_kexec_finish(void)

void __init tdx_early_init(void) { - struct tdx_module_args args = { - .rdx = TDCS_NOTIFY_ENABLES, - .r9 = -1ULL, - }; u64 cc_mask; u32 eax, sig[3];

@@ -951,7 +973,7 @@ void __init tdx_early_init(void) cc_set_mask(cc_mask);

/* Kernel does not use NOTIFY_ENABLES and does not need random #VEs */ - tdcall(TDG_VM_WR, &args); + tdg_vm_wr(TDCS_NOTIFY_ENABLES, 0, -1ULL);

/* * All bits above GPA width are reserved and kernel treats shared bit diff --git a/arch/x86/include/asm/shared/tdx.h b/arch/x86/include/asm/shared/tdx.h index fdfd41511b02..7e12cfa28bec 100644 --- a/arch/x86/include/asm/shared/tdx.h +++ b/arch/x86/include/asm/shared/tdx.h @@ -16,6 +16,7 @@ #define TDG_VP_VEINFO_GET 3 #define TDG_MR_REPORT 4 #define TDG_MEM_PAGE_ACCEPT 6 +#define TDG_VM_RD 7 #define TDG_VM_WR 8

/* TDCS fields. To be used by TDG.VM.WR and TDG.VM.RD module calls */