[PATCH 0/3] KVM: arm64: Normalize cache configuration

From: Akihiko Odaki
Date: Sun Dec 11 2022 - 00:18:08 EST


Before this change, the cache configuration of the physical CPU was
exposed to vcpus. This is problematic because the cache configuration a
vcpu sees varies when it migrates between vcpus with different cache
configurations.

Fabricate cache configuration from arm64_ftr_reg_ctrel0.sys_val, which
holds the CTR_EL0 value the userspace sees regardless of which physical
CPU it resides on.

HCR_TID2 is now always set as it is troublesome to detect the difference
of cache configurations among physical CPUs.

CSSELR_EL1 is now held in the memory instead of the corresponding
phyisccal register as the fabricated cache configuration may have a
cache level which does not exist in the physical CPU, and setting the
physical CSSELR_EL1 for the level results in an UNKNOWN behavior.

CLIDR_EL1 and CCSIDR_EL1 are now writable from the userspace so that
the VMM can restore the values saved with the old kernel.

Akihiko Odaki (3):
arm64/sysreg: Add CCSIDR2_EL1
arm64/cache: Move CLIDR macro definitions
KVM: arm64: Normalize cache configuration

arch/arm64/include/asm/cache.h | 6 +
arch/arm64/include/asm/kvm_arm.h | 3 +-
arch/arm64/include/asm/kvm_emulate.h | 4 -
arch/arm64/include/asm/kvm_host.h | 6 +-
arch/arm64/kernel/cacheinfo.c | 5 -
arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 2 -
arch/arm64/kvm/reset.c | 1 +
arch/arm64/kvm/sys_regs.c | 232 ++++++++++++---------
arch/arm64/tools/sysreg | 5 +
9 files changed, 153 insertions(+), 111 deletions(-)

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2.38.1