| Message ID | 20210422214708.716164-1-sathyanarayanan.kuppuswamy@linux.intel.com |
|---|---|
| Headers | show |
| Series | Add multiprocessor wake-up support | expand |
On 4/22/21 3:01 PM, Borislav Petkov wrote: > On Thu, Apr 22, 2021 at 02:47:05PM -0700, Kuppuswamy Sathyanarayanan wrote: >> Add multiprocessor wakeup support using MADT ACPI table for x86 >> platforms. It uses mailbox based mechanism to wake up the APs. You >> can get more details about the ACPI table and mailbox protocol in >> Guest-Host-Communication Interface (GHCI) for Intel Trust Domain >> Extensions (Intel TDX) specification document (sec 4.1) >> >> https://software.intel.com/content/dam/develop/external/us/en/documents/intel-tdx-guest-hypervisor-communication-interface.pdf >> >> Changes since v1: >> * Removed signoff from Rob and Erik. > > For the future: please do not resend your patchset immediately but give > reviewers time to have a look at it. > > Your current patchset comprises of only 3 patches - now imagine if it > were, 15, or 20 or more? Now also imagine if you were not the only one > submitter who would resend immediately... you'd soon have maintainers > drowning in email - not that they don't do so already anyway. > > While waiting, you could read > > Documentation/process/submitting-patches.rst Sorry for the trouble. I will keep it in mind for next submission. > > for example. > > Thx. >
On Thu, Apr 22, 2021 at 11:47 PM Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > ACPICA commit f1ee04207a212f6c519441e7e25397649ebc4cea > > Add Multiprocessor Wakeup Mailbox Structure definition. It is useful > in parsing MADT Wake table. > > Link: https://github.com/acpica/acpica/commit/f1ee0420 > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> I'm expecting to receive this patch from Erik at one point, so I'm guessing that it's been added to this series for reference. > --- > include/acpi/actbl2.h | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h > index b2362600b9ff..7dce422f6119 100644 > --- a/include/acpi/actbl2.h > +++ b/include/acpi/actbl2.h > @@ -733,6 +733,20 @@ struct acpi_madt_multiproc_wakeup { > u64 base_address; > }; > > +#define ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE 2032 > +#define ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE 2048 > + > +struct acpi_madt_multiproc_wakeup_mailbox { > + u16 command; > + u16 reserved; /* reserved - must be zero */ > + u32 apic_id; > + u64 wakeup_vector; > + u8 reserved_os[ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE]; /* reserved for OS use */ > + u8 reserved_firmware[ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE]; /* reserved for firmware use */ > +}; > + > +#define ACPI_MP_WAKE_COMMAND_WAKEUP 1 > + > /* > * Common flags fields for MADT subtables > */ > -- > 2.25.1 >
On Thu, Apr 22, 2021 at 11:47 PM Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > As per ACPI specification r6.4, sec 5.2.12.19, a new sub > structure – multiprocessor wake-up structure - is added to the > ACPI Multiple APIC Description Table (MADT) to describe the > information of the mailbox. If a platform firmware produces the > multiprocessor wake-up structure, then OS may use this new > mailbox-based mechanism to wake up the APs. > > Add ACPI MADT wake table parsing support for x86 platform and if > MADT wake table is present, update apic->wakeup_secondary_cpu with > new API which uses MADT wake mailbox to wake-up CPU. > > Co-developed-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > Reviewed-by: Andi Kleen <ak@linux.intel.com> > --- > arch/x86/include/asm/apic.h | 3 ++ > arch/x86/kernel/acpi/boot.c | 56 +++++++++++++++++++++++++++++++++ > arch/x86/kernel/apic/probe_32.c | 8 +++++ > arch/x86/kernel/apic/probe_64.c | 8 +++++ > 4 files changed, 75 insertions(+) > > diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h > index 412b51e059c8..3e94e1f402ea 100644 > --- a/arch/x86/include/asm/apic.h > +++ b/arch/x86/include/asm/apic.h > @@ -487,6 +487,9 @@ static inline unsigned int read_apic_id(void) > return apic->get_apic_id(reg); > } > > +typedef int (*wakeup_cpu_handler)(int apicid, unsigned long start_eip); > +extern void acpi_wake_cpu_handler_update(wakeup_cpu_handler handler); > + > extern int default_apic_id_valid(u32 apicid); > extern int default_acpi_madt_oem_check(char *, char *); > extern void default_setup_apic_routing(void); > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > index 14cd3186dc77..a4a6b97910e1 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -65,6 +65,9 @@ int acpi_fix_pin2_polarity __initdata; > static u64 acpi_lapic_addr __initdata = APIC_DEFAULT_PHYS_BASE; > #endif > > +static struct acpi_madt_multiproc_wakeup_mailbox *acpi_mp_wake_mailbox; > +static u64 acpi_mp_wake_mailbox_paddr; > + > #ifdef CONFIG_X86_IO_APIC > /* > * Locks related to IOAPIC hotplug > @@ -329,6 +332,29 @@ acpi_parse_lapic_nmi(union acpi_subtable_headers * header, const unsigned long e > return 0; > } > > +static void acpi_mp_wake_mailbox_init(void) > +{ > + if (acpi_mp_wake_mailbox) > + return; > + > + acpi_mp_wake_mailbox = memremap(acpi_mp_wake_mailbox_paddr, > + sizeof(*acpi_mp_wake_mailbox), MEMREMAP_WB); > +} > + > +static int acpi_wakeup_cpu(int apicid, unsigned long start_ip) > +{ > + acpi_mp_wake_mailbox_init(); > + > + if (!acpi_mp_wake_mailbox) > + return -EINVAL; > + > + WRITE_ONCE(acpi_mp_wake_mailbox->apic_id, apicid); > + WRITE_ONCE(acpi_mp_wake_mailbox->wakeup_vector, start_ip); > + WRITE_ONCE(acpi_mp_wake_mailbox->command, ACPI_MP_WAKE_COMMAND_WAKEUP); > + > + return 0; > +} > + > #endif /*CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1086,6 +1112,30 @@ static int __init acpi_parse_madt_lapic_entries(void) > } > return 0; > } > + > +static int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, > + const unsigned long end) > +{ > + struct acpi_madt_multiproc_wakeup *mp_wake; > + > + if (acpi_mp_wake_mailbox) > + return -EINVAL; > + > + if (!IS_ENABLED(CONFIG_SMP)) > + return -ENODEV; > + > + mp_wake = (struct acpi_madt_multiproc_wakeup *) header; > + if (BAD_MADT_ENTRY(mp_wake, end)) > + return -EINVAL; > + > + acpi_table_print_madt_entry(&header->common); > + > + acpi_mp_wake_mailbox_paddr = mp_wake->base_address; > + > + acpi_wake_cpu_handler_update(acpi_wakeup_cpu); > + > + return 0; > +} > #endif /* CONFIG_X86_LOCAL_APIC */ > > #ifdef CONFIG_X86_IO_APIC > @@ -1284,6 +1334,12 @@ static void __init acpi_process_madt(void) > > smp_found_config = 1; > } > + > + /* > + * Parse MADT MP Wake entry. > + */ > + acpi_table_parse_madt(ACPI_MADT_TYPE_MULTIPROC_WAKEUP, > + acpi_parse_mp_wake, 1); > } > if (error == -EINVAL) { > /* > diff --git a/arch/x86/kernel/apic/probe_32.c b/arch/x86/kernel/apic/probe_32.c > index a61f642b1b90..d450014841b2 100644 > --- a/arch/x86/kernel/apic/probe_32.c > +++ b/arch/x86/kernel/apic/probe_32.c > @@ -207,3 +207,11 @@ int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id) > } > return 0; > } > + > +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) > +{ > + struct apic **drv; > + > + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) > + (*drv)->wakeup_secondary_cpu = handler; > +} > diff --git a/arch/x86/kernel/apic/probe_64.c b/arch/x86/kernel/apic/probe_64.c > index c46720f185c0..986dbb68d3c4 100644 > --- a/arch/x86/kernel/apic/probe_64.c > +++ b/arch/x86/kernel/apic/probe_64.c > @@ -50,3 +50,11 @@ int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id) > } > return 0; > } > + > +void __init acpi_wake_cpu_handler_update(wakeup_cpu_handler handler) > +{ > + struct apic **drv; > + > + for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) > + (*drv)->wakeup_secondary_cpu = handler; > +} Although I've looked at this patch already, I now realize that according to the spec the mailbox is only suitable for the first AP wakeup during system initialization. Shouldn't the original handler be restored then to handle subsequent wakeups?
On 4/23/21 5:33 AM, Rafael J. Wysocki wrote: > On Thu, Apr 22, 2021 at 11:47 PM Kuppuswamy Sathyanarayanan > <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: >> >> ACPICA commit f1ee04207a212f6c519441e7e25397649ebc4cea >> >> Add Multiprocessor Wakeup Mailbox Structure definition. It is useful >> in parsing MADT Wake table. >> >> Link: https://github.com/acpica/acpica/commit/f1ee0420 >> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > > I'm expecting to receive this patch from Erik at one point, so I'm > guessing that it's been added to this series for reference. Yes. Since I had dependent patches, Erik sent it to me for submission. > >> --- >> include/acpi/actbl2.h | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h >> index b2362600b9ff..7dce422f6119 100644 >> --- a/include/acpi/actbl2.h >> +++ b/include/acpi/actbl2.h >> @@ -733,6 +733,20 @@ struct acpi_madt_multiproc_wakeup { >> u64 base_address; >> }; >> >> +#define ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE 2032 >> +#define ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE 2048 >> + >> +struct acpi_madt_multiproc_wakeup_mailbox { >> + u16 command; >> + u16 reserved; /* reserved - must be zero */ >> + u32 apic_id; >> + u64 wakeup_vector; >> + u8 reserved_os[ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE]; /* reserved for OS use */ >> + u8 reserved_firmware[ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE]; /* reserved for firmware use */ >> +}; >> + >> +#define ACPI_MP_WAKE_COMMAND_WAKEUP 1 >> + >> /* >> * Common flags fields for MADT subtables >> */ >> -- >> 2.25.1 >> -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
On 4/23/21 6:05 AM, Rafael J. Wysocki wrote: > Although I've looked at this patch already, I now realize that > according to the spec the mailbox is only suitable for the first AP > wakeup during system initialization. > > Shouldn't the original handler be restored then to handle subsequent wakeups? For TDX use case, since it does not support CPU hotplug/offline features, once the AP is turned on, it will never be off-lined and hence need not support subsequent wakeups. AFAIK, this MADT wake table is mainly defined for TDX use case. Please also check the TDX GHCI spec, sec 4.1. For each TD-guest, application processor, the mailbox can be used once for the wakeup command. After the guest-application processor takes the action according to the command, the intention is the mailbox will no longer be checked by the guest-application processor. Other guest processors can continue using the mailbox for the next command. -- Sathyanarayanan Kuppuswamy Linux Kernel Developer
> -----Original Message----- > From: Rafael J. Wysocki <rafael@kernel.org> > Sent: Friday, April 23, 2021 5:34 AM > To: Kuppuswamy Sathyanarayanan > <sathyanarayanan.kuppuswamy@linux.intel.com>; Kaneda, Erik > <erik.kaneda@intel.com> > Cc: Rafael J Wysocki <rjw@rjwysocki.net>; Thomas Gleixner > <tglx@linutronix.de>; Ingo Molnar <mingo@redhat.com>; H . Peter Anvin > <hpa@zytor.com>; Peter Zijlstra <peterz@infradead.org>; Len Brown > <lenb@kernel.org>; Moore, Robert <robert.moore@intel.com>; ACPI Devel > Maling List <linux-acpi@vger.kernel.org>; open list:ACPI COMPONENT > ARCHITECTURE (ACPICA) <devel@acpica.org>; Linux Kernel Mailing List > <linux-kernel@vger.kernel.org>; the arch/x86 maintainers > <x86@kernel.org> > Subject: Re: [PATCH v2 1/3] ACPICA: ACPI 6.4: MADT: add Multiprocessor > Wakeup Mailbox Structure > > On Thu, Apr 22, 2021 at 11:47 PM Kuppuswamy Sathyanarayanan > <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > > > ACPICA commit f1ee04207a212f6c519441e7e25397649ebc4cea > > > > Add Multiprocessor Wakeup Mailbox Structure definition. It is useful > > in parsing MADT Wake table. > > > > Link: https://github.com/acpica/acpica/commit/f1ee0420 > > Signed-off-by: Kuppuswamy Sathyanarayanan > <sathyanarayanan.kuppuswamy@linux.intel.com> > > I'm expecting to receive this patch from Erik at one point, so I'm > guessing that it's been added to this series for reference. Hi Rafael, This patch has been Linux-ized so that you can take this and the SVKL patch. I was told that this was urgent for this merge window. Since they were simple, I thought it would be easier to have Sathya submit to Linux and ACPICA upstream separately. Going through this process made things a little more difficult so I'll be sure to communicate with you ahead of time if I do this again. Erik > > > --- > > include/acpi/actbl2.h | 14 ++++++++++++++ > > 1 file changed, 14 insertions(+) > > > > diff --git a/include/acpi/actbl2.h b/include/acpi/actbl2.h > > index b2362600b9ff..7dce422f6119 100644 > > --- a/include/acpi/actbl2.h > > +++ b/include/acpi/actbl2.h > > @@ -733,6 +733,20 @@ struct acpi_madt_multiproc_wakeup { > > u64 base_address; > > }; > > > > +#define ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE 2032 > > +#define ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE 2048 > > + > > +struct acpi_madt_multiproc_wakeup_mailbox { > > + u16 command; > > + u16 reserved; /* reserved - must be zero */ > > + u32 apic_id; > > + u64 wakeup_vector; > > + u8 reserved_os[ACPI_MULTIPROC_WAKEUP_MB_OS_SIZE]; /* > reserved for OS use */ > > + u8 > reserved_firmware[ACPI_MULTIPROC_WAKEUP_MB_FIRMWARE_SIZE]; /* > reserved for firmware use */ > > +}; > > + > > +#define ACPI_MP_WAKE_COMMAND_WAKEUP 1 > > + > > /* > > * Common flags fields for MADT subtables > > */ > > -- > > 2.25.1 > >
On Fri, Apr 23, 2021 at 7:58 PM Kuppuswamy, Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> wrote: > > > > On 4/23/21 6:05 AM, Rafael J. Wysocki wrote: > > Although I've looked at this patch already, I now realize that > > according to the spec the mailbox is only suitable for the first AP > > wakeup during system initialization. > > > > Shouldn't the original handler be restored then to handle subsequent wakeups? > > For TDX use case, since it does not support CPU hotplug/offline features, once > the AP is turned on, it will never be off-lined and hence need not support > subsequent wakeups. > > AFAIK, this MADT wake table is mainly defined for TDX use case. > > Please also check the TDX GHCI spec, sec 4.1. > > For each TD-guest, application processor, the mailbox can be used once for the > wakeup command. After the guest-application processor takes the action according > to the command, the intention is the mailbox will no longer be checked by the > guest-application processor. Other guest processors can continue using the mailbox > for the next command. But this patch modifies generic code and the ACPI mechanism used by it is generic. TDX is not even mentioned by the spec section pointed to by the changelog. IMO it should at least ensure that the AP wakeup callback will return an error on an attempt to use it more than once on a given CPU.