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author | Joerg Roedel <jroedel@suse.de> | 2020-09-07 15:16:10 +0200 |
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committer | Borislav Petkov <bp@suse.de> | 2020-09-09 11:33:20 +0200 |
commit | 094794f59720d7e877a1eeb372ecedeed6b441ab (patch) | |
tree | 90bf02f1584235a544dff87863dd9674398ba158 /arch/x86/kernel | |
parent | 3ecacdbd23956a549d93023f86adc87b4a9d6520 (diff) | |
download | linux-094794f59720d7e877a1eeb372ecedeed6b441ab.tar.gz linux-094794f59720d7e877a1eeb372ecedeed6b441ab.tar.bz2 linux-094794f59720d7e877a1eeb372ecedeed6b441ab.zip |
x86/sev-es: Support CPU offline/online
Add a play_dead handler when running under SEV-ES. This is needed
because the hypervisor can't deliver an SIPI request to restart the AP.
Instead, the kernel has to issue a VMGEXIT to halt the VCPU until the
hypervisor wakes it up again.
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20200907131613.12703-70-joro@8bytes.org
Diffstat (limited to 'arch/x86/kernel')
-rw-r--r-- | arch/x86/kernel/sev-es.c | 63 |
1 files changed, 63 insertions, 0 deletions
diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 9ad36ce92b82..d1bcd0dca583 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -29,6 +29,8 @@ #include <asm/realmode.h> #include <asm/traps.h> #include <asm/svm.h> +#include <asm/smp.h> +#include <asm/cpu.h> #define DR7_RESET_VALUE 0x400 @@ -518,6 +520,65 @@ static bool __init sev_es_setup_ghcb(void) return true; } +#ifdef CONFIG_HOTPLUG_CPU +static void sev_es_ap_hlt_loop(void) +{ + struct ghcb_state state; + struct ghcb *ghcb; + + ghcb = sev_es_get_ghcb(&state); + + while (true) { + vc_ghcb_invalidate(ghcb); + ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP); + ghcb_set_sw_exit_info_1(ghcb, 0); + ghcb_set_sw_exit_info_2(ghcb, 0); + + sev_es_wr_ghcb_msr(__pa(ghcb)); + VMGEXIT(); + + /* Wakeup signal? */ + if (ghcb_sw_exit_info_2_is_valid(ghcb) && + ghcb->save.sw_exit_info_2) + break; + } + + sev_es_put_ghcb(&state); +} + +/* + * Play_dead handler when running under SEV-ES. This is needed because + * the hypervisor can't deliver an SIPI request to restart the AP. + * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the + * hypervisor wakes it up again. + */ +static void sev_es_play_dead(void) +{ + play_dead_common(); + + /* IRQs now disabled */ + + sev_es_ap_hlt_loop(); + + /* + * If we get here, the VCPU was woken up again. Jump to CPU + * startup code to get it back online. + */ + start_cpu0(); +} +#else /* CONFIG_HOTPLUG_CPU */ +#define sev_es_play_dead native_play_dead +#endif /* CONFIG_HOTPLUG_CPU */ + +#ifdef CONFIG_SMP +static void __init sev_es_setup_play_dead(void) +{ + smp_ops.play_dead = sev_es_play_dead; +} +#else +static inline void sev_es_setup_play_dead(void) { } +#endif + static void __init alloc_runtime_data(int cpu) { struct sev_es_runtime_data *data; @@ -566,6 +627,8 @@ void __init sev_es_init_vc_handling(void) setup_vc_stacks(cpu); } + sev_es_setup_play_dead(); + /* Secondary CPUs use the runtime #VC handler */ initial_vc_handler = (unsigned long)safe_stack_exc_vmm_communication; } |