ACPI tables aren't available if Linux runs as guest of the hypervisor
Jailhouse. This makes the 8250 driver probe for all platform UARTs as
it assumes that all platform are present in case of !ACPI. Jailhouse
will stop execution of Linux guest due to port access violation.
So far, these access violations could be solved by tuning the
8250.nr_uarts parameter but it has limitations: We can, e.g., only map
consecutive platform UARTs to Linux, and only in the sequence 0x3f8,
0x2f8, 0x3e8, 0x2e8.
Beginning from setup_data version 2, Jailhouse will place information of
available platform UARTs in setup_data. This allows for selective
activation of platform UARTs.
This patch queries the setup_data version and activates only available
UARTS. It comes with backward compatibility, and will still support
older setup_data versions. In this case, Linux falls back to the old
behaviour.
Signed-off-by: Ralf Ramsauer <ralf.ramsa...@oth-regensburg.de>
---
arch/x86/include/uapi/asm/bootparam.h | 1 +
arch/x86/kernel/jailhouse.c | 74 ++++++++++++++++++++++++---
2 files changed, 69 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/uapi/asm/bootparam.h
b/arch/x86/include/uapi/asm/bootparam.h
index a06cbf019744..2d6a40cbf3df 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -146,6 +146,7 @@ struct jailhouse_setup_data {
__u32 apic_khz;
__u8 standard_ioapic;
__u8 cpu_ids[255];
+ __u32 flags;
} __attribute__((packed));
/* The so-called "zeropage" */
diff --git a/arch/x86/kernel/jailhouse.c b/arch/x86/kernel/jailhouse.c
index 108c48d0d40e..3b73647b2456 100644
--- a/arch/x86/kernel/jailhouse.c
+++ b/arch/x86/kernel/jailhouse.c
@@ -11,6 +11,7 @@
#include <linux/acpi_pmtmr.h>
#include <linux/kernel.h>
#include <linux/reboot.h>
+#include <linux/serial_8250.h>
#include <asm/apic.h>
#include <asm/cpu.h>
#include <asm/hypervisor.h>
@@ -20,6 +21,10 @@
#include <asm/reboot.h>
#include <asm/setup.h>
+#define SETUP_DATA_FLAGS_PERMIT_PCUART(n) (1 << (n))
+#define SETUP_DATA_FLAGS_HAS_PCUART(flags, n) \
+ !!(flags & SETUP_DATA_FLAGS_PERMIT_PCUART(n))
+
static __initdata struct jailhouse_setup_data setup_data;
static unsigned int precalibrated_tsc_khz;
@@ -76,11 +81,13 @@ static void __init jailhouse_get_smp_config(unsigned int
early)
.type = IOAPIC_DOMAIN_STRICT,
.ops = &mp_ioapic_irqdomain_ops,
};
+#ifdef CONFIG_SERIAL_8250
struct mpc_intsrc mp_irq = {
.type = MP_INTSRC,
.irqtype = mp_INT,
.irqflag = MP_IRQPOL_ACTIVE_HIGH | MP_IRQTRIG_EDGE,
};
+#endif
unsigned int cpu;
jailhouse_x2apic_init();
@@ -97,12 +104,16 @@ static void __init jailhouse_get_smp_config(unsigned int
early)
if (setup_data.standard_ioapic) {
mp_register_ioapic(0, 0xfec00000, gsi_top, &ioapic_cfg);
- /* Register 1:1 mapping for legacy UART IRQs 3 and 4 */
- mp_irq.srcbusirq = mp_irq.dstirq = 3;
- mp_save_irq(&mp_irq);
+#ifdef CONFIG_SERIAL_8250
+ if (setup_data.version < 2) {
+ /* Register 1:1 mapping for legacy UART IRQs 3 and 4 */
+ mp_irq.srcbusirq = mp_irq.dstirq = 3;
+ mp_save_irq(&mp_irq);
- mp_irq.srcbusirq = mp_irq.dstirq = 4;
- mp_save_irq(&mp_irq);
+ mp_irq.srcbusirq = mp_irq.dstirq = 4;
+ mp_save_irq(&mp_irq);
+ }
+#endif
}
}
@@ -135,6 +146,42 @@ static int __init jailhouse_pci_arch_init(void)
return 0;
}
+#ifdef CONFIG_SERIAL_8250
+static const u16 pcuart_base[] = {
+ 0x3f8,
+ 0x2f8,
+ 0x3e8,
+ 0x2e8,
+};
+
+static void jailhouse_serial_fixup(int port, struct uart_port *up,
+ u32 *capabilites)
+{
+ struct mpc_intsrc mp_irq = {
+ .type = MP_INTSRC,
+ .irqtype = mp_INT,
+ .irqflag = MP_IRQPOL_ACTIVE_HIGH | MP_IRQTRIG_EDGE,
+ };
+ unsigned int n;
+
+ for (n = 0; n < ARRAY_SIZE(pcuart_base); n++) {
+ if (pcuart_base[n] != up->iobase)
+ continue;
+
+ if (SETUP_DATA_FLAGS_HAS_PCUART(setup_data.flags, n)) {
+ pr_info("Enabling UART%u (port 0x%lx)\n", n,
+ up->iobase);
+ mp_irq.srcbusirq = mp_irq.dstirq = up->irq;
+ mp_save_irq(&mp_irq);
+ } else {
+ /* Deactivate UART if access isn't allowed */
+ up->iobase = 0;
+ }
+ break;
+ }
+}
+#endif
+
static void __init jailhouse_init_platform(void)
{
u64 pa_data = boot_params.hdr.setup_data;
@@ -162,8 +209,12 @@ static void __init jailhouse_init_platform(void)
memcpy(&header, mapping, sizeof(header));
early_memunmap(mapping, sizeof(header));
+ /*
+ * Version 2 extends version 1 by four byte. We still do
+ * support version 1.
+ */
if (header.type == SETUP_JAILHOUSE &&
- header.len >= sizeof(setup_data)) {
+ header.len >= (sizeof(setup_data) - 4)) {
pa_data += offsetof(struct setup_data, data);
mapping = early_memremap(pa_data, sizeof(setup_data));
@@ -195,6 +246,17 @@ static void __init jailhouse_init_platform(void)
* are none in a non-root cell.
*/
disable_acpi();
+
+#ifdef CONFIG_SERIAL_8250
+ /* Since setup_data.version 2 we have flags that indicate availability
+ * of platform UARTs.
+ *
+ * In case of version 1, we don't know which UARTs belong Linux. In
+ * this case, unconditionally register 1:1 mapping for legacy UART IRQs
+ * 3 and 4 */
+ if (setup_data.version > 1)
+ serial8250_set_isa_configurator(jailhouse_serial_fixup);
+#endif
}
bool jailhouse_paravirt(void)
--
2.22.0
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