| Message ID | 20200428151725.31091-74-joro@8bytes.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86: SEV-ES Guest Support | expand |
On Tue, Apr 28, 2020 at 05:17:23PM +0200, Joerg Roedel wrote: > From: Joerg Roedel <jroedel@suse.de> > > 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. When the > hypervisor would deliver and SIPI is wakes up the VCPU instead. That last sentence needs fixing. Also, that explanation belongs as comment over sev_es_ap_hlt_loop() because commit messages are not that easy to find. > Signed-off-by: Joerg Roedel <jroedel@suse.de> > --- > arch/x86/include/uapi/asm/svm.h | 1 + > arch/x86/kernel/sev-es.c | 58 +++++++++++++++++++++++++++++++++ > 2 files changed, 59 insertions(+) > > diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h > index a19ce9681ec2..20a05839dd9a 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_AP_HLT_LOOP 0x80000004 > #define SVM_VMGEXIT_AP_JUMP_TABLE 0x80000005 > #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 > #define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1 > diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c > index 28725c38e6fb..00a5d0483730 100644 > --- a/arch/x86/kernel/sev-es.c > +++ b/arch/x86/kernel/sev-es.c > @@ -32,6 +32,8 @@ > #include <asm/processor.h> > #include <asm/traps.h> > #include <asm/svm.h> > +#include <asm/smp.h> > +#include <asm/cpu.h> > > #define DR7_RESET_VALUE 0x400 > > @@ -448,6 +450,60 @@ 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(); > + > + /* Wakup Signal? */ "Wakeup" > + if (ghcb_is_valid_sw_exit_info_2(ghcb) && > + ghcb->save.sw_exit_info_2 != 0) No need for the "!= 0". > + break; > + } > + > + sev_es_put_ghcb(&state); > +} ...
diff --git a/arch/x86/include/uapi/asm/svm.h b/arch/x86/include/uapi/asm/svm.h index a19ce9681ec2..20a05839dd9a 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_AP_HLT_LOOP 0x80000004 #define SVM_VMGEXIT_AP_JUMP_TABLE 0x80000005 #define SVM_VMGEXIT_SET_AP_JUMP_TABLE 0 #define SVM_VMGEXIT_GET_AP_JUMP_TABLE 1 diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 28725c38e6fb..00a5d0483730 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -32,6 +32,8 @@ #include <asm/processor.h> #include <asm/traps.h> #include <asm/svm.h> +#include <asm/smp.h> +#include <asm/cpu.h> #define DR7_RESET_VALUE 0x400 @@ -448,6 +450,60 @@ 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(); + + /* Wakup Signal? */ + if (ghcb_is_valid_sw_exit_info_2(ghcb) && + ghcb->save.sw_exit_info_2 != 0) + break; + } + + sev_es_put_ghcb(&state); +} + +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_cpu(); +} +#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 sev_es_alloc_runtime_data(int cpu) { struct sev_es_runtime_data *data; @@ -540,6 +596,8 @@ void __init sev_es_init_vc_handling(void) sev_es_setup_vc_stack(cpu); } + sev_es_setup_play_dead(); + xa_init_flags(&sev_es_cpuid_cache, XA_FLAGS_LOCK_IRQ); sev_es_cpuid_cache_initialized = true;