KVM: arm64: Correctly handle ACCDATA_EL1 traps

As we blindly reset some HFGxTR_EL2 bits to 0, we also randomly trap
unsuspecting sysregs that have their trap bits with a negative
polarity.

ACCDATA_EL1 is one such register that can be accessed by the guest,
causing a splat on the host as we don't have a proper handler for
it.

Adding such handler addresses the issue, though there are a number
of other registers missing as the current architecture documentation
doesn't describe them yet.
Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Miguel Luis <miguel.luis@oracle.com>
Reviewed-by: Jing Zhang <jingzhangos@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230815183903.2735724-11-maz@kernel.org

arch/arm64/include/asm/sysreg.h

@@ -387,6 +387,8 @@
 #define SYS_ICC_IGRPEN0_EL1		sys_reg(3, 0, 12, 12, 6)
 #define SYS_ICC_IGRPEN1_EL1		sys_reg(3, 0, 12, 12, 7)
 
+#define SYS_ACCDATA_EL1			sys_reg(3, 0, 13, 0, 5)
+
 #define SYS_CNTKCTL_EL1			sys_reg(3, 0, 14, 1, 0)
 
 #define SYS_AIDR_EL1			sys_reg(3, 1, 0, 0, 7)

arch/arm64/kvm/sys_regs.c

@@ -2151,6 +2151,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	{ SYS_DESC(SYS_CONTEXTIDR_EL1), access_vm_reg, reset_val, CONTEXTIDR_EL1, 0 },
 	{ SYS_DESC(SYS_TPIDR_EL1), NULL, reset_unknown, TPIDR_EL1 },
 
+	{ SYS_DESC(SYS_ACCDATA_EL1), undef_access },
+
 	{ SYS_DESC(SYS_SCXTNUM_EL1), undef_access },
 
 	{ SYS_DESC(SYS_CNTKCTL_EL1), NULL, reset_val, CNTKCTL_EL1, 0},