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authorJames Morse <james.morse@arm.com>2020-02-20 19:58:38 +0300
committerMarc Zyngier <maz@kernel.org>2020-02-22 14:01:47 +0300
commit8c2d146ee7a2e0782eea4dd70fddc1c837140136 (patch)
tree2a61fec4e43a9ebc5d677e0f2c227c898655d76d /arch
parent5c37f1ae1c335800d16b207cb578009c695dcd39 (diff)
downloadlinux-8c2d146ee7a2e0782eea4dd70fddc1c837140136.tar.xz
KVM: arm64: Define our own swab32() to avoid a uapi static inline
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@arm.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20200220165839.256881-3-james.morse@arm.com
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/include/asm/kvm_hyp.h7
-rw-r--r--arch/arm64/kvm/hyp/vgic-v2-cpuif-proxy.c4
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);
}