KVM: arm64: Treat CTR_EL0 as a VM feature ID register

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CTR_EL0 is currently handled as an invariant register, thus
guests will be presented with the host value of that register.

Add emulation for CTR_EL0 based on a per VM value. Userspace can
switch off DIC and IDC bits and reduce DminLine and IminLine sizes.
Naturally, ensure CTR_EL0 is trapped (HCR_EL2.TID2=1) any time that a
VM's CTR_EL0 differs from hardware.

Signed-off-by: Sebastian Ott <sebott@redhat.com>
Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
Link: https://lore.kernel.org/r/20240619174036.483943-8-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

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Sebastian Ott 2024-06-19 17:40:33 +00:00 • committed by Oliver Upton

parent f1ff3fc520

commit 2843cae266

2 changed files with 14 additions and 10 deletions

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4

arch/arm64/include/asm/kvm_host.h

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20

arch/arm64/kvm/sys_regs.c

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