From: James Morse <james.morse@xxxxxxx> KVM uses swab32() when mediating GIC MMIO accesses if the GICV is badly aligned, and the host and guest differ in endianness. arm64 doesn't provide a __arch_swab32(), so __fswab32() is always backed by the macro implementation that the compiler reduces to a single instruction. But the static-inline causes problems for KVM if the compiler chooses not to inline this function, it may not be located in the __hyp_text where __vgic_v2_perform_cpuif_access() needs it. Create our own __kvm_swab32() macro that calls ___constant_swab32() directly. This way we know it will always be inlined. Signed-off-by: James Morse <james.morse@xxxxxxx> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx> Link: https://lore.kernel.org/r/20200220165839.256881-3-james.morse@xxxxxxx --- arch/arm64/include/asm/kvm_hyp.h | 7 +++++++ arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c | 4 ++-- 2 files changed, 9 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h index 97f21cc66657..5fde137b5150 100644 --- a/arch/arm64/include/asm/kvm_hyp.h +++ b/arch/arm64/include/asm/kvm_hyp.h @@ -47,6 +47,13 @@ #define read_sysreg_el2(r) read_sysreg_elx(r, _EL2, _EL1) #define write_sysreg_el2(v,r) write_sysreg_elx(v, r, _EL2, _EL1) +/* + * Without an __arch_swab32(), we fall back to ___constant_swab32(), but the + * static inline can allow the compiler to out-of-line this. KVM always wants + * the macro version as its always inlined. + */ +#define __kvm_swab32(x) ___constant_swab32(x) + int __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu); void __vgic_v3_save_state(struct kvm_vcpu *vcpu); diff --git a/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c b/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c index 29ee1feba4eb..4f3a087e36d5 100644 --- a/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c +++ b/arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c @@ -69,14 +69,14 @@ int __hyp_text __vgic_v2_perform_cpuif_access(struct kvm_vcpu *vcpu) u32 data = vcpu_get_reg(vcpu, rd); if (__is_be(vcpu)) { /* guest pre-swabbed data, undo this for writel() */ - data = swab32(data); + data = __kvm_swab32(data); } writel_relaxed(data, addr); } else { u32 data = readl_relaxed(addr); if (__is_be(vcpu)) { /* guest expects swabbed data */ - data = swab32(data); + data = __kvm_swab32(data); } vcpu_set_reg(vcpu, rd, data); } -- 2.20.1
