diff options
Diffstat (limited to 'arch/x86/coco')
| -rw-r--r-- | arch/x86/coco/core.c | 12 | ||||
| -rw-r--r-- | arch/x86/coco/tdx/tdx.c | 47 |
2 files changed, 59 insertions, 0 deletions
diff --git a/arch/x86/coco/core.c b/arch/x86/coco/core.c index fc1365dd927e..3f3008783e05 100644 --- a/arch/x86/coco/core.c +++ b/arch/x86/coco/core.c @@ -87,9 +87,18 @@ EXPORT_SYMBOL_GPL(cc_platform_has); u64 cc_mkenc(u64 val) { + /* + * Both AMD and Intel use a bit in the page table to indicate + * encryption status of the page. + * + * - for AMD, bit *set* means the page is encrypted + * - for Intel *clear* means encrypted. + */ switch (vendor) { case CC_VENDOR_AMD: return val | cc_mask; + case CC_VENDOR_INTEL: + return val & ~cc_mask; default: return val; } @@ -97,9 +106,12 @@ u64 cc_mkenc(u64 val) u64 cc_mkdec(u64 val) { + /* See comment in cc_mkenc() */ switch (vendor) { case CC_VENDOR_AMD: return val & ~cc_mask; + case CC_VENDOR_INTEL: + return val | cc_mask; default: return val; } diff --git a/arch/x86/coco/tdx/tdx.c b/arch/x86/coco/tdx/tdx.c index 4b57880e45b0..96b2611baac5 100644 --- a/arch/x86/coco/tdx/tdx.c +++ b/arch/x86/coco/tdx/tdx.c @@ -5,8 +5,12 @@ #define pr_fmt(fmt) "tdx: " fmt #include <linux/cpufeature.h> +#include <asm/coco.h> #include <asm/tdx.h> +/* TDX module Call Leaf IDs */ +#define TDX_GET_INFO 1 + /* * Wrapper for standard use of __tdx_hypercall with no output aside from * return code. @@ -31,8 +35,47 @@ void __tdx_hypercall_failed(void) panic("TDVMCALL failed. TDX module bug?"); } +/* + * Used for TDX guests to make calls directly to the TD module. This + * should only be used for calls that have no legitimate reason to fail + * or where the kernel can not survive the call failing. + */ +static inline void tdx_module_call(u64 fn, u64 rcx, u64 rdx, u64 r8, u64 r9, + struct tdx_module_output *out) +{ + if (__tdx_module_call(fn, rcx, rdx, r8, r9, out)) + panic("TDCALL %lld failed (Buggy TDX module!)\n", fn); +} + +static u64 get_cc_mask(void) +{ + struct tdx_module_output out; + unsigned int gpa_width; + + /* + * TDINFO TDX module call is used to get the TD execution environment + * information like GPA width, number of available vcpus, debug mode + * information, etc. More details about the ABI can be found in TDX + * Guest-Host-Communication Interface (GHCI), section 2.4.2 TDCALL + * [TDG.VP.INFO]. + * + * The GPA width that comes out of this call is critical. TDX guests + * can not meaningfully run without it. + */ + tdx_module_call(TDX_GET_INFO, 0, 0, 0, 0, &out); + + gpa_width = out.rcx & GENMASK(5, 0); + + /* + * The highest bit of a guest physical address is the "sharing" bit. + * Set it for shared pages and clear it for private pages. + */ + return BIT_ULL(gpa_width - 1); +} + void __init tdx_early_init(void) { + u64 cc_mask; u32 eax, sig[3]; cpuid_count(TDX_CPUID_LEAF_ID, 0, &eax, &sig[0], &sig[2], &sig[1]); @@ -42,5 +85,9 @@ void __init tdx_early_init(void) setup_force_cpu_cap(X86_FEATURE_TDX_GUEST); + cc_set_vendor(CC_VENDOR_INTEL); + cc_mask = get_cc_mask(); + cc_set_mask(cc_mask); + pr_info("Guest detected\n"); } |