[tip:x86/platform] x86/jailhouse: Avoid access of unsupported platform resources

[tip-bot for Jan Kiszka]

Commit-ID:  0d7c1e22183b9ddaa0b3bf30ece6577741bc13b3
Gitweb:     https://git.kernel.org/tip/0d7c1e22183b9ddaa0b3bf30ece6577741bc13b3
Author:     Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
AuthorDate: Mon, 27 Nov 2017 09:11:50 +0100
Committer:  Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Sun, 14 Jan 2018 21:11:56 +0100

x86/jailhouse: Avoid access of unsupported platform resources

Non-root cells do not have CMOS access, thus the warm reset cannot be
enabled. There is no RTC, thus also no wall clock. Furthermore, there
are no ISA IRQs and no PIC.

Also disable probing of i8042 devices that are typically blocked for
non-root cells. In theory, access could also be granted to a non-root
cell, provided the root cell is not using the devices. But there is no
concrete scenario in sight, and disabling probing over Jailhouse allows
to build generic kernels that keep CONFIG_SERIO enabled for use in
normal systems.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: jailhouse-dev@xxxxxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/39b68cc2c496501c9d95e6f40e5d76e3053c3908.1511770314.git.jan.kiszka@xxxxxxxxxxx

---
 arch/x86/kernel/jailhouse.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index 34cf9d3..b9f116d 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -13,6 +13,7 @@
 #include <asm/apic.h>
 #include <asm/cpu.h>
 #include <asm/hypervisor.h>
+#include <asm/i8259.h>
 #include <asm/setup.h>
 
 static __initdata struct jailhouse_setup_data setup_data;
@@ -32,6 +33,11 @@ static uint32_t __init jailhouse_detect(void)
 	return jailhouse_cpuid_base();
 }
 
+static void jailhouse_get_wallclock(struct timespec *now)
+{
+	memset(now, 0, sizeof(*now));
+}
+
 static void __init jailhouse_timer_init(void)
 {
 	lapic_timer_frequency = setup_data.apic_khz * (1000 / HZ);
@@ -77,11 +83,18 @@ static void __init jailhouse_init_platform(void)
 	struct setup_data header;
 	void *mapping;
 
+	x86_init.irqs.pre_vector_init	= x86_init_noop;
 	x86_init.timers.timer_init	= jailhouse_timer_init;
 	x86_init.mpparse.get_smp_config	= jailhouse_get_smp_config;
 
 	x86_platform.calibrate_cpu	= jailhouse_get_tsc;
 	x86_platform.calibrate_tsc	= jailhouse_get_tsc;
+	x86_platform.get_wallclock	= jailhouse_get_wallclock;
+	x86_platform.legacy.rtc		= 0;
+	x86_platform.legacy.warm_reset	= 0;
+	x86_platform.legacy.i8042	= X86_LEGACY_I8042_PLATFORM_ABSENT;
+
+	legacy_pic			= &null_legacy_pic;
 
 	while (pa_data) {
 		mapping = early_memremap(pa_data, sizeof(header));