diff options
| author | Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:16:11 +0200 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2020-09-09 18:02:35 +0200 |
| commit | 4ca68e023b11e4d5908bf9ee326fab01111d77d5 (patch) | |
| tree | 874f57bbc6627e3f64668d2845051e1ea03cc15f /arch/x86 | |
| parent | 094794f59720d7e877a1eeb372ecedeed6b441ab (diff) | |
x86/sev-es: Handle NMI State
When running under SEV-ES, the kernel has to tell the hypervisor when to
open the NMI window again after an NMI was injected. This is done with
an NMI-complete message to the hypervisor.
Add code to the kernel's NMI handler to send this message right at the
beginning of do_nmi(). This always allows nesting NMIs.
[ bp: Mark __sev_es_nmi_complete() noinstr:
vmlinux.o: warning: objtool: exc_nmi()+0x17: call to __sev_es_nmi_complete()
leaves .noinstr.text section
While at it, use __pa_nodebug() for the same reason due to
CONFIG_DEBUG_VIRTUAL=y:
vmlinux.o: warning: objtool: __sev_es_nmi_complete()+0xd9: call to __phys_addr()
leaves .noinstr.text section ]
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-71-joro@8bytes.org
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/sev-es.h | 7 | ||||
| -rw-r--r-- | arch/x86/include/uapi/asm/svm.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/nmi.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/sev-es.c | 18 |
4 files changed, 32 insertions, 0 deletions
diff --git a/arch/x86/include/asm/sev-es.h b/arch/x86/include/asm/sev-es.h index db88e1c3442d..e919f09ae33c 100644 --- a/arch/x86/include/asm/sev-es.h +++ b/arch/x86/include/asm/sev-es.h @@ -96,10 +96,17 @@ static __always_inline void sev_es_ist_exit(void) __sev_es_ist_exit(); } extern int sev_es_setup_ap_jump_table(struct real_mode_header *rmh); +extern void __sev_es_nmi_complete(void); +static __always_inline void sev_es_nmi_complete(void) +{ + if (static_branch_unlikely(&sev_es_enable_key)) + __sev_es_nmi_complete(); +} #else static inline void sev_es_ist_enter(struct pt_regs *regs) { } static inline void sev_es_ist_exit(void) { } static inline int sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { return 0; } +static inline void sev_es_nmi_complete(void) { } #endif #endif diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index c1dcf3e114e4..a7a3403645e5 100644 --- a/arch/x86/include/uapi/asm/svm.h +++ b/arch/x86/include/uapi/asm/svm.h @@ -84,6 +84,7 @@ /* SEV-ES software-defined VMGEXIT events */ #define SVM_VMGEXIT_MMIO_READ 0x80000001 #define SVM_VMGEXIT_MMIO_WRITE 0x80000002 +#define SVM_VMGEXIT_NMI_COMPLETE 0x80000003 #define SVM_VMGEXIT_AP_HLT_LOOP 0x80000004 #define SVM_VMGEXIT_AP_JUMP_TABLE 0x80000005 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index 4c89c4d3cb82..56b64d779856 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -478,6 +478,12 @@ DEFINE_IDTENTRY_RAW(exc_nmi) { bool irq_state; + /* + * Re-enable NMIs right here when running as an SEV-ES guest. This might + * cause nested NMIs, but those can be handled safely. + */ + sev_es_nmi_complete(); + if (IS_ENABLED(CONFIG_SMP) && arch_cpu_is_offline(smp_processor_id())) return; diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index d1bcd0dca583..b6518e96dedb 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -408,6 +408,24 @@ static bool vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt, /* Include code shared with pre-decompression boot stage */ #include "sev-es-shared.c" +void noinstr __sev_es_nmi_complete(void) +{ + struct ghcb_state state; + struct ghcb *ghcb; + + ghcb = sev_es_get_ghcb(&state); + + vc_ghcb_invalidate(ghcb); + ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE); + ghcb_set_sw_exit_info_1(ghcb, 0); + ghcb_set_sw_exit_info_2(ghcb, 0); + + sev_es_wr_ghcb_msr(__pa_nodebug(ghcb)); + VMGEXIT(); + + sev_es_put_ghcb(&state); +} + static u64 get_jump_table_addr(void) { struct ghcb_state state; |