linux_dsm_epyc7002/arch/x86/include
David Woodhouse b8ab21e017 x86/apic: Fix x2apic enablement without interrupt remapping
[ Upstream commit 26573a97746c7a99f394f9d398ce91a8853b3b89 ]

Currently, Linux as a hypervisor guest will enable x2apic only if there are
no CPUs present at boot time with an APIC ID above 255.

Hotplugging a CPU later with a higher APIC ID would result in a CPU which
cannot be targeted by external interrupts.

Add a filter in x2apic_apic_id_valid() which can be used to prevent such
CPUs from coming online, and allow x2apic to be enabled even if they are
present at boot time.

Fixes: ce69a78450 ("x86/apic: Enable x2APIC without interrupt remapping under KVM")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20201024213535.443185-2-dwmw2@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-30 11:52:59 +01:00
..
asm x86/apic: Fix x2apic enablement without interrupt remapping 2020-12-30 11:52:59 +01:00
uapi/asm x86/kvm: Reserve KVM_FEATURE_MSI_EXT_DEST_ID 2020-10-28 13:52:05 -04:00