linux/arch/arm64
Christoffer Dall b9f8ca4db4 KVM: arm64: Defer saving/restoring 32-bit sysregs to vcpu load/put
When running a 32-bit VM (EL1 in AArch32), the AArch32 system registers
can be deferred to vcpu load/put on VHE systems because neither
the host kernel nor host userspace uses these registers.

Note that we can't save DBGVCR32_EL2 conditionally based on the state of
the debug dirty flag on VHE after this change, because during
vcpu_load() we haven't calculated a valid debug flag yet, and when we've
restored the register during vcpu_load() we also have to save it during
vcpu_put().  This means that we'll always restore/save the register for
VHE on load/put, but luckily vcpu load/put are called rarely, so saving
an extra register unconditionally shouldn't significantly hurt
performance.

We can also not defer saving FPEXC32_32 because this register only holds
a guest-valid value for 32-bit guests during the exit path when the
guest has used FPSIMD registers and restored the register in the early
assembly handler from taking the EL2 fault, and therefore we have to
check if fpsimd is enabled for the guest in the exit path and save the
register then, for both VHE and non-VHE guests.

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
2018-03-19 10:53:18 +00:00
..
boot ARM: SoC device tree updates for 4.16 2018-02-01 16:07:54 -08:00
configs ARM: SoC platform updates for 4.16 2018-02-01 16:17:40 -08:00
crypto crypto: arm64/sha512 - fix/improve new v8.2 Crypto Extensions code 2018-01-26 01:10:36 +11:00
include KVM: arm64: Prepare to handle deferred save/restore of 32-bit registers 2018-03-19 10:53:18 +00:00
kernel KVM: arm64: Avoid storing the vcpu pointer on the stack 2018-03-19 10:53:09 +00:00
kvm KVM: arm64: Defer saving/restoring 32-bit sysregs to vcpu load/put 2018-03-19 10:53:18 +00:00
lib arm64: uaccess: Mask __user pointers for __arch_{clear, copy_*}_user 2018-02-06 22:53:40 +00:00
mm arm64: Enforce BBM for huge IO/VMAP mappings 2018-02-22 11:25:53 +00:00
net bpf, arm64: fix out of bounds access in tail call 2018-02-22 16:06:28 -08:00
xen arm64: mm: Add additional parameter to uaccess_ttbr0_disable 2018-01-17 13:57:49 +01:00
Kconfig arm64: Add software workaround for Falkor erratum 1041 2018-02-06 22:53:13 +00:00
Kconfig.debug
Kconfig.platforms clk: meson-axg: add clock controller drivers 2017-12-14 10:19:37 +01:00
Makefile arm64: ftrace: emit ftrace-mod.o contents through code 2017-12-01 13:04:59 +00:00