The following commit has been merged into the x86/tdx branch of tip:
Commit-ID: 5081e8fadb809253c911b349b01d87c5b4e3fec5
Gitweb: https://git.kernel.org/tip/5081e8fadb809253c911b349b01d87c5b4e3fec5
Author: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 04 Nov 2024 12:38:00 +02:00
Committer: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
CommitterDate: Thu, 07 Nov 2024 10:26:16 -08:00
x86/tdx: Introduce wrappers to read and write TD metadata
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@xxxxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Reviewed-by: Kai Huang <kai.huang@xxxxxxxxx>
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/all/20241104103803.195705-2-kirill.shutemov%40linux.intel.com
---
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 327c45c..c74bb9e 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 fdfd415..7e12cfa 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 */
|