| Message ID | 20240823232327.2408869-4-yunhong.jiang@linux.intel.com |
|---|---|
| State | New |
| Headers | show |
| Series | x86/hyperv: Support wakeup mailbox for VTL2 TDX guest | expand |
On Mon, Sep 02, 2024 at 03:35:06AM +0000, Michael Kelley wrote: > From: Yunhong Jiang <yunhong.jiang@linux.intel.com> Sent: Friday, August 23, 2024 4:23 PM > > > > When a TDX guest boots with the device tree instead of ACPI, it can > > reuse the ACPI multiprocessor wakeup mechanism to wake up application > > processors(AP), without introducing a new mechanism from scrach. > > > > In the ACPI spec, two structures are defined to wake up the APs: the > > multiprocessor wakeup structure and the multiprocessor wakeup mailbox > > structure. The multiprocessor wakeup structure is passed to OS through a > > Multiple APIC Description Table(MADT), one field specifying the physical > > address of the multiprocessor wakeup mailbox structure. The OS sends > > a message to firmware through the multiprocessor wakeup mailbox > > structure, to bring up the APs. > > > > In device tree environment, the multiprocessor wakeup structure is not > > used, to reduce the dependency on the generic ACPI table. The > > information defined in this structure is defined in the properties of > > cpus node in the device tree. The "wakeup-mailbox-addr" property > > specifies the physical address of the multiprocessor wakeup mailbox > > structure. The OS will follow the ACPI spec to send the message to the > > firmware to bring up the APs. > > > > Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com> > > --- > > MAINTAINERS | 1 + > > arch/x86/Kconfig | 2 +- > > arch/x86/include/asm/acpi.h | 1 - > > arch/x86/include/asm/madt_wakeup.h | 16 +++++++++++++ > > arch/x86/kernel/madt_wakeup.c | 38 ++++++++++++++++++++++++++++++ > > 5 files changed, 56 insertions(+), 2 deletions(-) > > create mode 100644 arch/x86/include/asm/madt_wakeup.h > > > > diff --git a/MAINTAINERS b/MAINTAINERS > > index 5555a3bbac5f..900de6501eba 100644 > > --- a/MAINTAINERS > > +++ b/MAINTAINERS > > @@ -288,6 +288,7 @@ T: git > > git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm > > F: Documentation/ABI/testing/configfs-acpi > > F: Documentation/ABI/testing/sysfs-bus-acpi > > F: Documentation/firmware-guide/acpi/ > > +F: arch/x86/include/asm/madt_wakeup.h > > F: arch/x86/kernel/acpi/ > > F: arch/x86/kernel/madt_playdead.S > > F: arch/x86/kernel/madt_wakeup.c > > diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig > > index d422247b2882..dba46dd30049 100644 > > --- a/arch/x86/Kconfig > > +++ b/arch/x86/Kconfig > > @@ -1123,7 +1123,7 @@ config X86_LOCAL_APIC > > config ACPI_MADT_WAKEUP > > def_bool y > > depends on X86_64 > > - depends on ACPI > > + depends on ACPI || OF > > depends on SMP > > depends on X86_LOCAL_APIC > > > > diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h > > index 21bc53f5ed0c..0e082303ca26 100644 > > --- a/arch/x86/include/asm/acpi.h > > +++ b/arch/x86/include/asm/acpi.h > > @@ -83,7 +83,6 @@ union acpi_subtable_headers; > > int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, > > const unsigned long end); > > > > -void asm_acpi_mp_play_dead(u64 reset_vector, u64 pgd_pa); > > > > /* > > * Check if the CPU can handle C2 and deeper > > diff --git a/arch/x86/include/asm/madt_wakeup.h > > b/arch/x86/include/asm/madt_wakeup.h > > new file mode 100644 > > index 000000000000..a8cd50af581a > > --- /dev/null > > +++ b/arch/x86/include/asm/madt_wakeup.h > > @@ -0,0 +1,16 @@ > > +/* SPDX-License-Identifier: GPL-2.0 */ > > +#ifndef __ASM_X86_MADT_WAKEUP_H > > +#define __ASM_X86_MADT_WAKEUP_H > > + > > +void asm_acpi_mp_play_dead(u64 reset_vector, u64 pgd_pa); > > + > > +#if defined(CONFIG_OF) && defined(CONFIG_ACPI_MADT_WAKEUP) > > +u64 dtb_parse_mp_wake(void); > > +#else > > +static inline u64 dtb_parse_mp_wake(void) > > +{ > > + return 0; > > +} > > +#endif > > + > > +#endif /* __ASM_X86_MADT_WAKEUP_H */ > > diff --git a/arch/x86/kernel/madt_wakeup.c b/arch/x86/kernel/madt_wakeup.c > > index d5ef6215583b..7257e7484569 100644 > > --- a/arch/x86/kernel/madt_wakeup.c > > +++ b/arch/x86/kernel/madt_wakeup.c > > @@ -14,6 +14,8 @@ > > #include <asm/nmi.h> > > #include <asm/processor.h> > > #include <asm/reboot.h> > > +#include <asm/madt_wakeup.h> > > +#include <asm/prom.h> > > > > /* Physical address of the Multiprocessor Wakeup Structure mailbox */ > > static u64 acpi_mp_wake_mailbox_paddr __ro_after_init; > > @@ -122,6 +124,7 @@ static int __init init_transition_pgtable(pgd_t *pgd) > > return 0; > > } > > > > +#ifdef CONFIG_ACPI > > static int __init acpi_mp_setup_reset(u64 reset_vector) > > { > > struct x86_mapping_info info = { > > @@ -168,6 +171,7 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) > > > > return 0; > > } > > +#endif > > When acpi_mp_setup_reset() is #ifdef'ed out because of CONFIG_ACPI > not being set, doesn't this generate compile warnings about > init_transition_pgtable(), alloc_pgt_page(), free_pgt_page(), etc. being > unused? > > It appears that the only code in madt_wakeup.c that is shared between > the ACPI and OF cases is acpi_wakeup_cpu()? Is that correct? Yes, the acpi_wakeup_cpu() is the only code. Interestingly that I don't see compilation warning for the functions you listed like alloc_pgt_page()/free_pgt_page() etc when built with CONFIG_ACPI disabled. Will check in deep and figure out the reason. > > > > > static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip) > > { > > @@ -226,6 +230,7 @@ static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip) > > return 0; > > } > > > > +#ifdef CONFIG_ACPI > > static void acpi_mp_disable_offlining(struct acpi_madt_multiproc_wakeup *mp_wake) > > { > > cpu_hotplug_disable_offlining(); > > @@ -290,3 +295,36 @@ int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, > > > > return 0; > > } > > +#endif /* CONFIG_ACPI */ > > + > > +#ifdef CONFIG_OF > > +u64 __init dtb_parse_mp_wake(void) > > +{ > > + struct device_node *node; > > + u64 mailaddr = 0; > > + > > + node = of_find_node_by_path("/cpus"); > > + if (!node) > > + return 0; > > + > > + if (of_property_match_string(node, "enable-method", "acpi-wakeup-mailbox") < 0) { > > + pr_err("No acpi wakeup mailbox enable-method\n"); > > + goto done; > > Patch 4 of this series unconditionally calls dtb_parse_mp_wake(), > so it will be called in normal VMs, as a well as SEV-SNP and TDX > kernels built for VTL 2 (assuming CONFIG_OF is set). Normal VMs > presumably won't be using DT and won't have the "/cpus" node, > so this function will silently do nothing, which is fine. But do you > expect the DT "/cpus" node to be present in an SEV-SNP VTL 2 > environment? If so, this function will either output some spurious > error messages, or SEV-SNP will use the ACPI wakeup mailbox > method, which is probably not what you want. > > Michael Yes, will fix the spurios error messages. Thank you for pointing out this. Thanks --jyh > > > + } > > + > > + if (of_property_read_u64(node, "wakeup-mailbox-addr", &mailaddr)) { > > + pr_err("Invalid wakeup mailbox addr\n"); > > + goto done; > > + } > > + acpi_mp_wake_mailbox_paddr = mailaddr; > > + pr_info("dt wakeup-mailbox: addr 0x%llx\n", mailaddr); > > + > > + /* No support for the MADT reset vector yet */ > > + cpu_hotplug_disable_offlining(); > > + apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu); > > + > > +done: > > + of_node_put(node); > > + return mailaddr; > > +} > > +#endif /* CONFIG_OF */ > > -- > > 2.25.1 > > >
diff --git a/MAINTAINERS b/MAINTAINERS index 5555a3bbac5f..900de6501eba 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -288,6 +288,7 @@ T: git git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm F: Documentation/ABI/testing/configfs-acpi F: Documentation/ABI/testing/sysfs-bus-acpi F: Documentation/firmware-guide/acpi/ +F: arch/x86/include/asm/madt_wakeup.h F: arch/x86/kernel/acpi/ F: arch/x86/kernel/madt_playdead.S F: arch/x86/kernel/madt_wakeup.c diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d422247b2882..dba46dd30049 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1123,7 +1123,7 @@ config X86_LOCAL_APIC config ACPI_MADT_WAKEUP def_bool y depends on X86_64 - depends on ACPI + depends on ACPI || OF depends on SMP depends on X86_LOCAL_APIC diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h index 21bc53f5ed0c..0e082303ca26 100644 --- a/arch/x86/include/asm/acpi.h +++ b/arch/x86/include/asm/acpi.h @@ -83,7 +83,6 @@ union acpi_subtable_headers; int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, const unsigned long end); -void asm_acpi_mp_play_dead(u64 reset_vector, u64 pgd_pa); /* * Check if the CPU can handle C2 and deeper diff --git a/arch/x86/include/asm/madt_wakeup.h b/arch/x86/include/asm/madt_wakeup.h new file mode 100644 index 000000000000..a8cd50af581a --- /dev/null +++ b/arch/x86/include/asm/madt_wakeup.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __ASM_X86_MADT_WAKEUP_H +#define __ASM_X86_MADT_WAKEUP_H + +void asm_acpi_mp_play_dead(u64 reset_vector, u64 pgd_pa); + +#if defined(CONFIG_OF) && defined(CONFIG_ACPI_MADT_WAKEUP) +u64 dtb_parse_mp_wake(void); +#else +static inline u64 dtb_parse_mp_wake(void) +{ + return 0; +} +#endif + +#endif /* __ASM_X86_MADT_WAKEUP_H */ diff --git a/arch/x86/kernel/madt_wakeup.c b/arch/x86/kernel/madt_wakeup.c index d5ef6215583b..7257e7484569 100644 --- a/arch/x86/kernel/madt_wakeup.c +++ b/arch/x86/kernel/madt_wakeup.c @@ -14,6 +14,8 @@ #include <asm/nmi.h> #include <asm/processor.h> #include <asm/reboot.h> +#include <asm/madt_wakeup.h> +#include <asm/prom.h> /* Physical address of the Multiprocessor Wakeup Structure mailbox */ static u64 acpi_mp_wake_mailbox_paddr __ro_after_init; @@ -122,6 +124,7 @@ static int __init init_transition_pgtable(pgd_t *pgd) return 0; } +#ifdef CONFIG_ACPI static int __init acpi_mp_setup_reset(u64 reset_vector) { struct x86_mapping_info info = { @@ -168,6 +171,7 @@ static int __init acpi_mp_setup_reset(u64 reset_vector) return 0; } +#endif static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip) { @@ -226,6 +230,7 @@ static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip) return 0; } +#ifdef CONFIG_ACPI static void acpi_mp_disable_offlining(struct acpi_madt_multiproc_wakeup *mp_wake) { cpu_hotplug_disable_offlining(); @@ -290,3 +295,36 @@ int __init acpi_parse_mp_wake(union acpi_subtable_headers *header, return 0; } +#endif /* CONFIG_ACPI */ + +#ifdef CONFIG_OF +u64 __init dtb_parse_mp_wake(void) +{ + struct device_node *node; + u64 mailaddr = 0; + + node = of_find_node_by_path("/cpus"); + if (!node) + return 0; + + if (of_property_match_string(node, "enable-method", "acpi-wakeup-mailbox") < 0) { + pr_err("No acpi wakeup mailbox enable-method\n"); + goto done; + } + + if (of_property_read_u64(node, "wakeup-mailbox-addr", &mailaddr)) { + pr_err("Invalid wakeup mailbox addr\n"); + goto done; + } + acpi_mp_wake_mailbox_paddr = mailaddr; + pr_info("dt wakeup-mailbox: addr 0x%llx\n", mailaddr); + + /* No support for the MADT reset vector yet */ + cpu_hotplug_disable_offlining(); + apic_update_callback(wakeup_secondary_cpu_64, acpi_wakeup_cpu); + +done: + of_node_put(node); + return mailaddr; +} +#endif /* CONFIG_OF */
When a TDX guest boots with the device tree instead of ACPI, it can reuse the ACPI multiprocessor wakeup mechanism to wake up application processors(AP), without introducing a new mechanism from scrach. In the ACPI spec, two structures are defined to wake up the APs: the multiprocessor wakeup structure and the multiprocessor wakeup mailbox structure. The multiprocessor wakeup structure is passed to OS through a Multiple APIC Description Table(MADT), one field specifying the physical address of the multiprocessor wakeup mailbox structure. The OS sends a message to firmware through the multiprocessor wakeup mailbox structure, to bring up the APs. In device tree environment, the multiprocessor wakeup structure is not used, to reduce the dependency on the generic ACPI table. The information defined in this structure is defined in the properties of cpus node in the device tree. The "wakeup-mailbox-addr" property specifies the physical address of the multiprocessor wakeup mailbox structure. The OS will follow the ACPI spec to send the message to the firmware to bring up the APs. Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com> --- MAINTAINERS | 1 + arch/x86/Kconfig | 2 +- arch/x86/include/asm/acpi.h | 1 - arch/x86/include/asm/madt_wakeup.h | 16 +++++++++++++ arch/x86/kernel/madt_wakeup.c | 38 ++++++++++++++++++++++++++++++ 5 files changed, 56 insertions(+), 2 deletions(-) create mode 100644 arch/x86/include/asm/madt_wakeup.h