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author | 2015-12-01 22:36:37 +0000 | |
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committer | 2016-05-20 15:40:03 +0200 | |
commit | 7d450e2821710718fd6703e9c486249cee913bab (patch) | |
tree | 02dc0e9f84440e3d77ee72f32e27d53bcedda758 /net/6lowpan | |
parent | KVM: arm/arm64: vgic-new: Export register access interface (diff) | |
download | linux-7d450e282171.tar.gz linux-7d450e282171.tar.bz2 linux-7d450e282171.zip |
KVM: arm/arm64: vgic-new: Add userland access to VGIC dist registers
Userland may want to save and restore the state of the in-kernel VGIC,
so we provide the code which takes a userland request and translate
that into calls to our MMIO framework.
From Christoffer:
When accessing the VGIC state from userspace we really don't want a VCPU
to be messing with the state at the same time, and the API specifies
that we should return -EBUSY if any VCPUs are running.
Check and prevent VCPUs from running by grabbing their mutexes, one by
one, and error out if we fail.
(Note: This could potentially be simplified to just do a simple check
and see if any VCPUs are running, and return -EBUSY then, without
enforcing the locking throughout the duration of the uaccess, if we
think that taking/releasing all these mutexes for every single GIC
register access is too heavyweight.)
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
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