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| author | Christoffer Dall <christoffer.dall@linaro.org> | 2023-02-09 20:58:20 +0300 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-02-11 13:13:30 +0300 |
| commit | 191e0e155521182051fc2f32dde237b6fde2b0b4 (patch) | |
| tree | ee99d2b595ccd538d2637740e317eccc533145d5 /arch/arm64/include/asm/kvm_mmu.h | |
| parent | 9f75b6d447d712b6ed9abc869eedf456fe7f5e9b (diff) | |
| download | linux-191e0e155521182051fc2f32dde237b6fde2b0b4.tar.xz | |
KVM: arm64: nv: Only toggle cache for virtual EL2 when SCTLR_EL2 changes
So far we were flushing almost the entire universe whenever a VM would
load/unload the SCTLR_EL1 and the two versions of that register had
different MMU enabled settings. This turned out to be so slow that it
prevented forward progress for a nested VM, because a scheduler timer
tick interrupt would always be pending when we reached the nested VM.
To avoid this problem, we consider the SCTLR_EL2 when evaluating if
caches are on or off when entering virtual EL2 (because this is the
value that we end up shadowing onto the hardware EL1 register).
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230209175820.1939006-19-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/include/asm/kvm_mmu.h')
| -rw-r--r-- | arch/arm64/include/asm/kvm_mmu.h | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h index e4a7e6369499..2890d57bec30 100644 --- a/arch/arm64/include/asm/kvm_mmu.h +++ b/arch/arm64/include/asm/kvm_mmu.h @@ -115,6 +115,7 @@ alternative_cb_end #include <asm/cache.h> #include <asm/cacheflush.h> #include <asm/mmu_context.h> +#include <asm/kvm_emulate.h> #include <asm/kvm_host.h> void kvm_update_va_mask(struct alt_instr *alt, @@ -192,7 +193,15 @@ struct kvm; static inline bool vcpu_has_cache_enabled(struct kvm_vcpu *vcpu) { - return (vcpu_read_sys_reg(vcpu, SCTLR_EL1) & 0b101) == 0b101; + u64 cache_bits = SCTLR_ELx_M | SCTLR_ELx_C; + int reg; + + if (vcpu_is_el2(vcpu)) + reg = SCTLR_EL2; + else + reg = SCTLR_EL1; + + return (vcpu_read_sys_reg(vcpu, reg) & cache_bits) == cache_bits; } static inline void __clean_dcache_guest_page(void *va, size_t size) |