cf72bc4816
The TDX module global metadata provides system-wide information about
the module.
TL;DR:
Use the TDH.SYS.RD SEAMCALL to tell if the module is good or not.
Long Version:
1) Only initialize TDX module with version 1.5 and later
TDX module 1.0 has some compatibility issues with the later versions of
module, as documented in the "Intel TDX module ABI incompatibilities
between TDX1.0 and TDX1.5" spec. Don't bother with module versions that
do not have a stable ABI.
2) Get the essential global metadata for module initialization
TDX reports a list of "Convertible Memory Region" (CMR) to tell the
kernel which memory is TDX compatible. The kernel needs to build a list
of memory regions (out of CMRs) as "TDX-usable" memory and pass them to
the TDX module. The kernel does this by constructing a list of "TD
Memory Regions" (TDMRs) to cover all these memory regions and passing
them to the TDX module.
Each TDMR is a TDX architectural data structure containing the memory
region that the TDMR covers, plus the information to track (within this
TDMR):
a) the "Physical Address Metadata Table" (PAMT) to track each TDX
memory page's status (such as which TDX guest "owns" a given page,
and
b) the "reserved areas" to tell memory holes that cannot be used as
TDX memory.
The kernel needs to get below metadata from the TDX module to build the
list of TDMRs:
a) the maximum number of supported TDMRs
b) the maximum number of supported reserved areas per TDMR and,
c) the PAMT entry size for each TDX-supported page size.
== Implementation ==
The TDX module has two modes of fetching the metadata: a one field at
a time, or all in one blob. Use the field at a time for now. It is
slower, but there just are not enough fields now to justify the
complexity of extra unpacking.
The err_free_tdxmem=>out_put_tdxmem goto looks wonky by itself. But
it is the first of a bunch of error handling that will get stuck at
its site.
[ dhansen: clean up changelog and add a struct to map between
the TDX module fields and 'struct tdx_tdmr_sysinfo' ]
Signed-off-by: Kai Huang <kai.huang@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lore.kernel.org/all/20231208170740.53979-8-dave.hansen%40intel.com
136 lines
3.4 KiB
C
136 lines
3.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_X86_SHARED_TDX_H
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#define _ASM_X86_SHARED_TDX_H
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#include <linux/bits.h>
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#include <linux/types.h>
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#define TDX_HYPERCALL_STANDARD 0
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#define TDX_CPUID_LEAF_ID 0x21
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#define TDX_IDENT "IntelTDX "
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/* TDX module Call Leaf IDs */
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#define TDG_VP_VMCALL 0
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#define TDG_VP_INFO 1
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#define TDG_VP_VEINFO_GET 3
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#define TDG_MR_REPORT 4
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#define TDG_MEM_PAGE_ACCEPT 6
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#define TDG_VM_WR 8
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/* TDCS fields. To be used by TDG.VM.WR and TDG.VM.RD module calls */
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#define TDCS_NOTIFY_ENABLES 0x9100000000000010
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/* TDX hypercall Leaf IDs */
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#define TDVMCALL_MAP_GPA 0x10001
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#define TDVMCALL_GET_QUOTE 0x10002
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#define TDVMCALL_REPORT_FATAL_ERROR 0x10003
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#define TDVMCALL_STATUS_RETRY 1
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/*
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* Bitmasks of exposed registers (with VMM).
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*/
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#define TDX_RDX BIT(2)
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#define TDX_RBX BIT(3)
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#define TDX_RSI BIT(6)
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#define TDX_RDI BIT(7)
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#define TDX_R8 BIT(8)
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#define TDX_R9 BIT(9)
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#define TDX_R10 BIT(10)
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#define TDX_R11 BIT(11)
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#define TDX_R12 BIT(12)
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#define TDX_R13 BIT(13)
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#define TDX_R14 BIT(14)
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#define TDX_R15 BIT(15)
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/*
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* These registers are clobbered to hold arguments for each
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* TDVMCALL. They are safe to expose to the VMM.
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* Each bit in this mask represents a register ID. Bit field
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* details can be found in TDX GHCI specification, section
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* titled "TDCALL [TDG.VP.VMCALL] leaf".
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*/
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#define TDVMCALL_EXPOSE_REGS_MASK \
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(TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8 | TDX_R9 | \
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TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15)
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/* TDX supported page sizes from the TDX module ABI. */
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#define TDX_PS_4K 0
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#define TDX_PS_2M 1
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#define TDX_PS_1G 2
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#define TDX_PS_NR (TDX_PS_1G + 1)
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#ifndef __ASSEMBLY__
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#include <linux/compiler_attributes.h>
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/*
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* Used in __tdcall*() to gather the input/output registers' values of the
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* TDCALL instruction when requesting services from the TDX module. This is a
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* software only structure and not part of the TDX module/VMM ABI
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*/
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struct tdx_module_args {
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/* callee-clobbered */
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u64 rcx;
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u64 rdx;
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u64 r8;
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u64 r9;
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/* extra callee-clobbered */
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u64 r10;
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u64 r11;
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/* callee-saved + rdi/rsi */
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u64 r12;
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u64 r13;
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u64 r14;
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u64 r15;
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u64 rbx;
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u64 rdi;
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u64 rsi;
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};
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/* Used to communicate with the TDX module */
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u64 __tdcall(u64 fn, struct tdx_module_args *args);
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u64 __tdcall_ret(u64 fn, struct tdx_module_args *args);
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u64 __tdcall_saved_ret(u64 fn, struct tdx_module_args *args);
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/* Used to request services from the VMM */
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u64 __tdx_hypercall(struct tdx_module_args *args);
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/*
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* Wrapper for standard use of __tdx_hypercall with no output aside from
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* return code.
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*/
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static inline u64 _tdx_hypercall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15)
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{
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struct tdx_module_args args = {
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.r10 = TDX_HYPERCALL_STANDARD,
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.r11 = fn,
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.r12 = r12,
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.r13 = r13,
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.r14 = r14,
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.r15 = r15,
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};
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return __tdx_hypercall(&args);
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}
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/* Called from __tdx_hypercall() for unrecoverable failure */
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void __noreturn __tdx_hypercall_failed(void);
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bool tdx_accept_memory(phys_addr_t start, phys_addr_t end);
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/*
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* The TDG.VP.VMCALL-Instruction-execution sub-functions are defined
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* independently from but are currently matched 1:1 with VMX EXIT_REASONs.
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* Reusing the KVM EXIT_REASON macros makes it easier to connect the host and
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* guest sides of these calls.
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*/
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static __always_inline u64 hcall_func(u64 exit_reason)
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{
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return exit_reason;
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}
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#endif /* !__ASSEMBLY__ */
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#endif /* _ASM_X86_SHARED_TDX_H */
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