diff options
| -rw-r--r-- | arch/x86/include/asm/tdx.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/mce/core.c | 15 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/tdx/tdx.c | 109 | ||||
| -rw-r--r-- | arch/x86/virt/vmx/tdx/tdx.h | 5 |
4 files changed, 133 insertions, 0 deletions
diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index c54948e1999c..eba178996d84 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -32,6 +32,8 @@ #ifndef __ASSEMBLY__ +#include <uapi/asm/mce.h> + /* * Used by the #VE exception handler to gather the #VE exception * info from the TDX module. This is a software only structure @@ -113,10 +115,12 @@ static inline u64 sc_retry(sc_func_t func, u64 fn, #define seamcall_saved_ret(_fn, _args) sc_retry(__seamcall_saved_ret, (_fn), (_args)) int tdx_cpu_enable(void); int tdx_enable(void); +const char *tdx_dump_mce_info(struct mce *m); #else static inline void tdx_init(void) { } static inline int tdx_cpu_enable(void) { return -ENODEV; } static inline int tdx_enable(void) { return -ENODEV; } +static inline const char *tdx_dump_mce_info(struct mce *m) { return NULL; } #endif /* CONFIG_INTEL_TDX_HOST */ #endif /* !__ASSEMBLY__ */ diff --git a/arch/x86/kernel/cpu/mce/core.c b/arch/x86/kernel/cpu/mce/core.c index 7b397370b4d6..00d2b6b1dc24 100644 --- a/arch/x86/kernel/cpu/mce/core.c +++ b/arch/x86/kernel/cpu/mce/core.c @@ -52,6 +52,7 @@ #include <asm/mce.h> #include <asm/msr.h> #include <asm/reboot.h> +#include <asm/tdx.h> #include "internal.h" @@ -228,11 +229,20 @@ static void wait_for_panic(void) panic("Panicing machine check CPU died"); } +static const char *mce_dump_aux_info(struct mce *m) +{ + if (boot_cpu_has_bug(X86_BUG_TDX_PW_MCE)) + return tdx_dump_mce_info(m); + + return NULL; +} + static noinstr void mce_panic(const char *msg, struct mce *final, char *exp) { struct llist_node *pending; struct mce_evt_llist *l; int apei_err = 0; + const char *memmsg; /* * Allow instrumentation around external facilities usage. Not that it @@ -283,6 +293,11 @@ static noinstr void mce_panic(const char *msg, struct mce *final, char *exp) } if (exp) pr_emerg(HW_ERR "Machine check: %s\n", exp); + + memmsg = mce_dump_aux_info(final); + if (memmsg) + pr_emerg(HW_ERR "Machine check: %s\n", memmsg); + if (!fake_panic) { if (panic_timeout == 0) panic_timeout = mca_cfg.panic_timeout; diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c index 06b04b9c3236..4d6826a76f78 100644 --- a/arch/x86/virt/vmx/tdx/tdx.c +++ b/arch/x86/virt/vmx/tdx/tdx.c @@ -27,6 +27,7 @@ #include <linux/log2.h> #include <linux/acpi.h> #include <linux/suspend.h> +#include <linux/acpi.h> #include <asm/page.h> #include <asm/special_insns.h> #include <asm/msr-index.h> @@ -35,6 +36,7 @@ #include <asm/tdx.h> #include <asm/intel-family.h> #include <asm/processor.h> +#include <asm/mce.h> #include "tdx.h" static u32 tdx_global_keyid __ro_after_init; @@ -942,6 +944,13 @@ static int construct_tdmrs(struct list_head *tmb_list, if (ret) tdmrs_free_pamt_all(tdmr_list); + /* + * The tdmr_info_list is read-only from here on out. + * Ensure that these writes are seen by other CPUs. + * Pairs with a smp_rmb() in is_pamt_page(). + */ + smp_wmb(); + return ret; } @@ -1235,6 +1244,106 @@ int tdx_enable(void) } EXPORT_SYMBOL_GPL(tdx_enable); +static bool is_pamt_page(unsigned long phys) +{ + struct tdmr_info_list *tdmr_list = &tdx_tdmr_list; + int i; + + /* Ensure that all remote 'tdmr_list' writes are visible: */ + smp_rmb(); + + /* + * The TDX module is no longer returning TDX_SYS_NOT_READY and + * is initialized. The 'tdmr_list' was initialized long ago + * and is now read-only. + */ + for (i = 0; i < tdmr_list->nr_consumed_tdmrs; i++) { + unsigned long base, size; + + tdmr_get_pamt(tdmr_entry(tdmr_list, i), &base, &size); + + if (phys >= base && phys < (base + size)) + return true; + } + + return false; +} + +/* + * Return whether the memory page at the given physical address is TDX + * private memory or not. + * + * This can be imprecise for two known reasons: + * 1. PAMTs are private memory and exist before the TDX module is + * ready and TDH_PHYMEM_PAGE_RDMD works. This is a relatively + * short window that occurs once per boot. + * 2. TDH_PHYMEM_PAGE_RDMD reflects the TDX module's knowledge of the + * page. However, the page can still cause #MC until it has been + * fully converted to shared using 64-byte writes like MOVDIR64B. + * Buggy hosts might still leave #MC-causing memory in place which + * this function can not detect. + */ +static bool paddr_is_tdx_private(unsigned long phys) +{ + struct tdx_module_args args = { + .rcx = phys & PAGE_MASK, + }; + u64 sret; + + if (!boot_cpu_has(X86_FEATURE_TDX_HOST_PLATFORM)) + return false; + + /* Get page type from the TDX module */ + sret = __seamcall_ret(TDH_PHYMEM_PAGE_RDMD, &args); + + /* + * The SEAMCALL will not return success unless there is a + * working, "ready" TDX module. Assume an absence of TDX + * private pages until SEAMCALL is working. + */ + if (sret) + return false; + + /* + * SEAMCALL was successful -- read page type (via RCX): + * + * - PT_NDA: Page is not used by the TDX module + * - PT_RSVD: Reserved for Non-TDX use + * - Others: Page is used by the TDX module + * + * Note PAMT pages are marked as PT_RSVD but they are also TDX + * private memory. + */ + switch (args.rcx) { + case PT_NDA: + return false; + case PT_RSVD: + return is_pamt_page(phys); + default: + return true; + } +} + +/* + * Some TDX-capable CPUs have an erratum. A write to TDX private + * memory poisons that memory, and a subsequent read of that memory + * triggers #MC. + * + * Help distinguish erratum-triggered #MCs from a normal hardware one. + * Just print additional message to show such #MC may be result of the + * erratum. + */ +const char *tdx_dump_mce_info(struct mce *m) +{ + if (!m || !mce_is_memory_error(m) || !mce_usable_address(m)) + return NULL; + + if (!paddr_is_tdx_private(m->addr)) + return NULL; + + return "TDX private memory error. Possible kernel bug."; +} + static __init int record_keyid_partitioning(u32 *tdx_keyid_start, u32 *nr_tdx_keyids) { diff --git a/arch/x86/virt/vmx/tdx/tdx.h b/arch/x86/virt/vmx/tdx/tdx.h index c0610f0bb88c..b701f69485d3 100644 --- a/arch/x86/virt/vmx/tdx/tdx.h +++ b/arch/x86/virt/vmx/tdx/tdx.h @@ -14,6 +14,7 @@ /* * TDX module SEAMCALL leaf functions */ +#define TDH_PHYMEM_PAGE_RDMD 24 #define TDH_SYS_KEY_CONFIG 31 #define TDH_SYS_INIT 33 #define TDH_SYS_RD 34 @@ -21,6 +22,10 @@ #define TDH_SYS_TDMR_INIT 36 #define TDH_SYS_CONFIG 45 +/* TDX page types */ +#define PT_NDA 0x0 +#define PT_RSVD 0x1 + /* * Global scope metadata field ID. * |