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authorJames Morse <james.morse@arm.com>2018-09-21 21:49:19 +0100
committerCatalin Marinas <catalin.marinas@arm.com>2018-10-19 15:37:25 +0100
commit4debef5510071032c6d5dace31ca1cc42a120073 (patch)
tree8c85a24a9c2d877e430f1d4987debe5d63123bac
parent4afe8e79da920bdf6698b01bc668fffc6758f37b (diff)
arm64: KVM: Guests can skip __install_bp_hardening_cb()s HYP work
enable_smccc_arch_workaround_1() passes NULL as the hyp_vecs start and end if the HVC conduit is in use, and ARM_SMCCC_ARCH_WORKAROUND_1 is detected. If the guest kernel happened to be built with KVM_INDIRECT_VECTORS, we go on to allocate a slot, memcpy() the empty workaround in and do the appropriate cache maintenance. This works as we always tell memcpy() the range is 0, so it never accesses the NULL src pointer, but we still do the cache maintenance. If hyp_vecs_start is NULL we know we're a guest, just update the fn like the !KVM_INDIRECT_VECTORS version. Reviewed-by: Julien Thierry <julien.thierry@arm.com> Acked-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: James Morse <james.morse@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
-rw-r--r--arch/arm64/kernel/cpu_errata.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c
index 9af8df96ec49..a509e35132d2 100644
--- a/arch/arm64/kernel/cpu_errata.c
+++ b/arch/arm64/kernel/cpu_errata.c
@@ -138,6 +138,15 @@ static void __install_bp_hardening_cb(bp_hardening_cb_t fn,
static DEFINE_SPINLOCK(bp_lock);
int cpu, slot = -1;
+ /*
+ * enable_smccc_arch_workaround_1() passes NULL for the hyp_vecs
+ * start/end if we're a guest. Skip the hyp-vectors work.
+ */
+ if (!hyp_vecs_start) {
+ __this_cpu_write(bp_hardening_data.fn, fn);
+ return;
+ }
+
spin_lock(&bp_lock);
for_each_possible_cpu(cpu) {
if (per_cpu(bp_hardening_data.fn, cpu) == fn) {