On 19.08.19 20:43, [email protected] wrote:
On August 19, 2019 10:22:07 AM PDT, Ralf Ramsauer
<[email protected]> wrote:
On 8/14/19 12:53 AM, [email protected] wrote:
On August 13, 2019 4:04:34 AM PDT, Jan Kiszka
<[email protected]> wrote:
On 13.08.19 11:32, [email protected] wrote:
On August 12, 2019 4:06:50 AM PDT, Ralf Ramsauer
<[email protected]> wrote:
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 <[email protected]>
---
arch/x86/include/uapi/asm/bootparam.h | 3 ++
arch/x86/kernel/jailhouse.c | 75
++++++++++++++++++++++++---
2 files changed, 72 insertions(+), 6 deletions(-)
diff --git a/arch/x86/include/uapi/asm/bootparam.h
b/arch/x86/include/uapi/asm/bootparam.h
index 6163b1afa7b3..2244c493c3c5 100644
--- a/arch/x86/include/uapi/asm/bootparam.h
+++ b/arch/x86/include/uapi/asm/bootparam.h
@@ -150,6 +150,9 @@ struct jailhouse_setup_data {
__u8 standard_ioapic;
__u8 cpu_ids[255];
} __attribute__((packed)) v1;
+ struct {
+ __u32 flags;
+ } __attribute__((packed)) v2;
} __attribute__((packed));
/* The so-called "zeropage" */
diff --git a/arch/x86/kernel/jailhouse.c
b/arch/x86/kernel/jailhouse.c
index e5ac35efc4b3..1c75de1496f3 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>
@@ -20,8 +21,13 @@
#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;
#define SETUP_DATA_V1_LEN (sizeof(setup_data.hdr) +
sizeof(setup_data.v1))
+#define SETUP_DATA_V2_LEN (SETUP_DATA_V1_LEN +
sizeof(setup_data.v2))
static unsigned int precalibrated_tsc_khz;
@@ -78,11 +84,13 @@ 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();
@@ -99,12 +107,16 @@ static void __init
jailhouse_get_smp_config(unsigned int early)
if (setup_data.v1.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.hdr.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
}
}
@@ -137,6 +149,42 @@ 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.v2.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;
@@ -186,7 +234,8 @@ static void __init
jailhouse_init_platform(void)
if (setup_data.hdr.version == 0 ||
setup_data.hdr.compatible_version !=
JAILHOUSE_SETUP_REQUIRED_VERSION ||
- (setup_data.hdr.version >= 1 && header.len <
SETUP_DATA_V1_LEN))
+ (setup_data.hdr.version == 1 && header.len <
SETUP_DATA_V1_LEN)
||
+ (setup_data.hdr.version >= 2 && header.len <
SETUP_DATA_V2_LEN))
goto unsupported;
pmtmr_ioport = setup_data.v1.pm_timer_address;
@@ -202,6 +251,20 @@ static void __init
jailhouse_init_platform(void)
* are none in a non-root cell.
*/
disable_acpi();
+
+#ifdef CONFIG_SERIAL_8250
+ /*
+ * There are flags inside setup_data that indicate availability
of
+ * platform UARTs since setup data version 2.
+ *
+ * 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.hdr.version > 1)
+ serial8250_set_isa_configurator(jailhouse_serial_fixup);
+#endif
+
return;
unsupported:
Or you could, you know, pass a data structure that already does
this... it's called DSDT.
At least by the time the boot process for Linux under Jailhouse was
designed
(~2015), ACPI was not able to express the minimal hardware we are
exposing. So
we went for "CONFIG_ACPI disabled", and that was rather simple.
There are some new knobs now to get rid of legacy platform
components.
But,
e.g., is it ACPI-compliant to expose a PM_TMR block, but nothing
else?
How would
you communicate pre-calibrated TSC and APIC frequencies?
Thanks,
Jan
If ACPI cannot represent something important, I'd like to bring that
to the attention of the ACPI committee so we can standardize whatever
is missing.
In an offlist discussion, Jan and I agreed that DSDTs should definitely
be considered and evaluated in the long run, but for the moment - and
for what I actually want to achieve with this patch - this should do
the
job.
I will send a v3 and address Jan's remarks on patch 1/2.
Thanks
Ralf
The request still remains, though: *please* contact me if there are things we
need to be able to express in ACPI and can't.
Thanks for the offer. I already provided two questions above.
Jan
--
Siemens AG, Corporate Technology, CT RDA IOT SES-DE
Corporate Competence Center Embedded Linux
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