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| author | Jan Kiszka <jan.kiszka@siemens.com> | 2017-11-27 09:11:43 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-01-14 21:11:53 +0100 |
| commit | 32c9c801a853f181448ed4e8730168c556f9e05a (patch) | |
| tree | 29e62e4f909bb9539ef30a32bc4faadb0bb0d321 /arch/x86/kernel/apic | |
| parent | Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ker... (diff) | |
| download | linux-32c9c801a853f181448ed4e8730168c556f9e05a.tar.xz linux-32c9c801a853f181448ed4e8730168c556f9e05a.zip | |
x86/apic: Install an empty physflat_init_apic_ldr
As the comment already stated, there is no need for setting up LDR (and
DFR) in physflat mode as it remains unused (see SDM, 10.6.2.1).
flat_init_apic_ldr only served as a placeholder for a nop operation so
far, causing no harm.
That will change when running over the Jailhouse hypervisor. Here we
must not touch LDR in a way that destroys the mapping originally set up
by the Linux root cell. Jailhouse enforces this setting in order to
efficiently validate any IPI requests sent by a cell.
Avoid a needless clash caused by flat_init_apic_ldr by installing a true
nop handler.
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: jailhouse-dev@googlegroups.com
Link: https://lkml.kernel.org/r/f9867d294cdae4d45ed89d3a2e6adb524f4f6794.1511770314.git.jan.kiszka@siemens.com
Diffstat (limited to 'arch/x86/kernel/apic')
| -rw-r--r-- | arch/x86/kernel/apic/apic_flat_64.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c index 25a87028cb3f..4b5547789713 100644 --- a/arch/x86/kernel/apic/apic_flat_64.c +++ b/arch/x86/kernel/apic/apic_flat_64.c @@ -218,6 +218,15 @@ static int physflat_acpi_madt_oem_check(char *oem_id, char *oem_table_id) return 0; } +static void physflat_init_apic_ldr(void) +{ + /* + * LDR and DFR are not involved in physflat mode, rather: + * "In physical destination mode, the destination processor is + * specified by its local APIC ID [...]." (Intel SDM, 10.6.2.1) + */ +} + static void physflat_send_IPI_allbutself(int vector) { default_send_IPI_mask_allbutself_phys(cpu_online_mask, vector); @@ -251,8 +260,7 @@ static struct apic apic_physflat __ro_after_init = { .dest_logical = 0, .check_apicid_used = NULL, - /* not needed, but shouldn't hurt: */ - .init_apic_ldr = flat_init_apic_ldr, + .init_apic_ldr = physflat_init_apic_ldr, .ioapic_phys_id_map = NULL, .setup_apic_routing = NULL, |