[PATCH v2 6/9] arm64: KVM: check ordering of all system register tables

Marc Zyngier
2014-05-20T16:55:56Z

We now have multiple tables for the various system registers
we trap. Make sure we check the order of all of them, as it is
critical that we get the order right (been there, done that...).

Reviewed-by: Anup Patel <anup.patel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/sys_regs.c | 22 ++++++++++++++++++++--
1 file changed, 20 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index e4a2113..98d60d1 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1280,14 +1280,32 @@ int kvm_arm_copy_sys_reg_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
return write_demux_regids(uindices);
}

+static int check_sysreg_table(const struct sys_reg_desc *table, unsigned int n)
+{
+ unsigned int i;
+
+ for (i = 1; i < n; i++) {
+ if (cmp_sys_reg(&table[i-1], &table[i]) >= 0) {
+ kvm_err("sys_reg table %p out of order (%d)\n", table, i - 1);
+ return 1;
+ }
+ }
+
+ return 0;
+}
+
void kvm_sys_reg_table_init(void)
{
unsigned int i;
struct sys_reg_desc clidr;

/* Make sure tables are unique and in order. */
- for (i = 1; i < ARRAY_SIZE(sys_reg_descs); i++)
- BUG_ON(cmp_sys_reg(&sys_reg_descs[i-1], &sys_reg_descs[i]) >= 0);
+ BUG_ON(check_sysreg_table(sys_reg_descs, ARRAY_SIZE(sys_reg_descs)));
+ BUG_ON(check_sysreg_table(cp14_regs, ARRAY_SIZE(cp14_regs)));
+ BUG_ON(check_sysreg_table(cp14_64_regs, ARRAY_SIZE(cp14_64_regs)));
+ BUG_ON(check_sysreg_table(cp15_regs, ARRAY_SIZE(cp15_regs)));
+ BUG_ON(check_sysreg_table(cp15_64_regs, ARRAY_SIZE(cp15_64_regs)));
+ BUG_ON(check_sysreg_table(invariant_sys_regs, ARRAY_SIZE(invariant_sys_regs)));

/* We abuse the reset function to overwrite the table itself. */
for (i = 0; i < ARRAY_SIZE(invariant_sys_regs); i++)
--
1.8.3.4