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SubjectRe: [RFC PATCH] x86/acpi: Prevent x2apic id -1 from being accounted
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Hi RongQing,

Is there an local x2apic whose ID is 0xFFFFFFFF in your machine?

At 04/08/2018 07:38 PM, Li RongQing wrote:
> local_apic_id of acpi_madt_local_x2apic is u32, it is converted to
> int when checked by default_apic_id_valid() and return true if it is
> larger than 0x7fffffff, this is wrong
>

For x2apic enabled systems,

- the byte length of X2APIC ID is 4, and it can be larger than
0x7fffffff in theory

- the ->apic_id_valid points to x2apic_apic_id_valid(), which always
return _ture_ , not default_apic_id_valid().

Thanks,
dou

> and if local_apic_id is invalid, we should prevent it from being
> accounted >
> This fixes a bug that Purley platform displays too many possible cpu
>
> Signed-off-by: Li RongQing <lirongqing@baidu.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Dou Liyang <douly.fnst@cn.fujitsu.com>
> ---
> arch/x86/include/asm/apic.h | 4 ++--
> arch/x86/kernel/acpi/boot.c | 10 ++++++----
> arch/x86/kernel/apic/apic_common.c | 2 +-
> arch/x86/kernel/apic/apic_numachip.c | 2 +-
> arch/x86/kernel/apic/x2apic.h | 2 +-
> arch/x86/kernel/apic/x2apic_phys.c | 2 +-
> arch/x86/kernel/apic/x2apic_uv_x.c | 2 +-
> arch/x86/xen/apic.c | 2 +-
> 8 files changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/arch/x86/include/asm/apic.h b/arch/x86/include/asm/apic.h
> index 40a3d3642f3a..08acd954f00e 100644
> --- a/arch/x86/include/asm/apic.h
> +++ b/arch/x86/include/asm/apic.h
> @@ -313,7 +313,7 @@ struct apic {
> /* Probe, setup and smpboot functions */
> int (*probe)(void);
> int (*acpi_madt_oem_check)(char *oem_id, char *oem_table_id);
> - int (*apic_id_valid)(int apicid);
> + int (*apic_id_valid)(u32 apicid);
> int (*apic_id_registered)(void);
>
> bool (*check_apicid_used)(physid_mask_t *map, int apicid);
> @@ -486,7 +486,7 @@ static inline unsigned int read_apic_id(void)
> return apic->get_apic_id(reg);
> }
>
> -extern int default_apic_id_valid(int apicid);
> +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 7a37d9357bc4..7412564dc2a7 100644
> --- a/arch/x86/kernel/acpi/boot.c
> +++ b/arch/x86/kernel/acpi/boot.c
> @@ -200,7 +200,7 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end)
> {
> struct acpi_madt_local_x2apic *processor = NULL;
> #ifdef CONFIG_X86_X2APIC
> - int apic_id;
> + u32 apic_id;
> u8 enabled;
> #endif
>
> @@ -222,10 +222,12 @@ acpi_parse_x2apic(struct acpi_subtable_header *header, const unsigned long end)
> * to not preallocating memory for all NR_CPUS
> * when we use CPU hotplug.
> */
> - if (!apic->apic_id_valid(apic_id) && enabled)
> + if (!apic->apic_id_valid(apic_id)) {
> printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
> - else
> - acpi_register_lapic(apic_id, processor->uid, enabled);
> + return 0;
> + }
> +
> + acpi_register_lapic(apic_id, processor->uid, enabled);
> #else
> printk(KERN_WARNING PREFIX "x2apic entry ignored\n");
> #endif
> diff --git a/arch/x86/kernel/apic/apic_common.c b/arch/x86/kernel/apic/apic_common.c
> index a360801779ae..02b4839478b1 100644
> --- a/arch/x86/kernel/apic/apic_common.c
> +++ b/arch/x86/kernel/apic/apic_common.c
> @@ -40,7 +40,7 @@ int default_check_phys_apicid_present(int phys_apicid)
> return physid_isset(phys_apicid, phys_cpu_present_map);
> }
>
> -int default_apic_id_valid(int apicid)
> +int default_apic_id_valid(u32 apicid)
> {
> return (apicid < 255);
> }
> diff --git a/arch/x86/kernel/apic/apic_numachip.c b/arch/x86/kernel/apic/apic_numachip.c
> index 134e04506ab4..78778b54f904 100644
> --- a/arch/x86/kernel/apic/apic_numachip.c
> +++ b/arch/x86/kernel/apic/apic_numachip.c
> @@ -56,7 +56,7 @@ static u32 numachip2_set_apic_id(unsigned int id)
> return id << 24;
> }
>
> -static int numachip_apic_id_valid(int apicid)
> +static int numachip_apic_id_valid(u32 apicid)
> {
> /* Trust what bootloader passes in MADT */
> return 1;
> diff --git a/arch/x86/kernel/apic/x2apic.h b/arch/x86/kernel/apic/x2apic.h
> index b107de381cb5..a49b3604027f 100644
> --- a/arch/x86/kernel/apic/x2apic.h
> +++ b/arch/x86/kernel/apic/x2apic.h
> @@ -1,6 +1,6 @@
> /* Common bits for X2APIC cluster/physical modes. */
>
> -int x2apic_apic_id_valid(int apicid);
> +int x2apic_apic_id_valid(u32 apicid);
> int x2apic_apic_id_registered(void);
> void __x2apic_send_IPI_dest(unsigned int apicid, int vector, unsigned int dest);
> unsigned int x2apic_get_apic_id(unsigned long id);
> diff --git a/arch/x86/kernel/apic/x2apic_phys.c b/arch/x86/kernel/apic/x2apic_phys.c
> index e2829bf40e4a..b5cf9e7b3830 100644
> --- a/arch/x86/kernel/apic/x2apic_phys.c
> +++ b/arch/x86/kernel/apic/x2apic_phys.c
> @@ -101,7 +101,7 @@ static int x2apic_phys_probe(void)
> }
>
> /* Common x2apic functions, also used by x2apic_cluster */
> -int x2apic_apic_id_valid(int apicid)
> +int x2apic_apic_id_valid(u32 apicid)
> {
> return 1;
> }
> diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c
> index f11910b44638..efaf2d4f9c3c 100644
> --- a/arch/x86/kernel/apic/x2apic_uv_x.c
> +++ b/arch/x86/kernel/apic/x2apic_uv_x.c
> @@ -557,7 +557,7 @@ static void uv_send_IPI_all(int vector)
> uv_send_IPI_mask(cpu_online_mask, vector);
> }
>
> -static int uv_apic_id_valid(int apicid)
> +static int uv_apic_id_valid(u32 apicid)
> {
> return 1;
> }
> diff --git a/arch/x86/xen/apic.c b/arch/x86/xen/apic.c
> index 2163888497d3..5e53bfbe5823 100644
> --- a/arch/x86/xen/apic.c
> +++ b/arch/x86/xen/apic.c
> @@ -112,7 +112,7 @@ static int xen_madt_oem_check(char *oem_id, char *oem_table_id)
> return xen_pv_domain();
> }
>
> -static int xen_id_always_valid(int apicid)
> +static int xen_id_always_valid(u32 apicid)
> {
> return 1;
> }
>


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