[PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware

Li Chen posted 4 patches 6 months, 3 weeks ago
Maintainers: "Michael S. Tsirkin" <mst@redhat.com>, Igor Mammedov <imammedo@redhat.com>, Ani Sinha <anisinha@redhat.com>, Shannon Zhao <shannon.zhaosl@gmail.com>, Peter Maydell <peter.maydell@linaro.org>, Eduardo Habkost <eduardo@habkost.net>, Marcel Apfelbaum <marcel.apfelbaum@gmail.com>, "Philippe Mathieu-Daudé" <philmd@linaro.org>, Yanan Wang <wangyanan55@huawei.com>, Zhao Liu <zhao1.liu@intel.com>, Song Gao <gaosong@loongson.cn>, Bibo Mao <maobibo@loongson.cn>, Jiaxun Yang <jiaxun.yang@flygoat.com>, Sunil V L <sunilvl@ventanamicro.com>, Palmer Dabbelt <palmer@dabbelt.com>, Alistair Francis <alistair.francis@wdc.com>, Weiwei Li <liwei1518@gmail.com>, Daniel Henrique Barboza <dbarboza@ventanamicro.com>, Liu Zhiwei <zhiwei_liu@linux.alibaba.com>, Paolo Bonzini <pbonzini@redhat.com>
There is a newer version of this series
[PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 6 months, 3 weeks ago
From: Li Chen <chenl311@chinatelecom.cn>

The virt machines always instantiate a PL011/16550 at UART0 and
describe it in ACPI (DSDT device node plus optional SPCR table).  When
the command line contains “-serial none” there is no backend attached to
that UART, yet the guest still discovers it via ACPI and may try to use
it as a console, causing unexpected results.

And also explicitly add "-serial stdio" in bios-tables-test.c to allow
serial device creation, otherwise DSDT assert would get failure because
"-nodefaults" will not create uart device by default:

```
stderr:
acpi-test: Warning! DSDT binary file mismatch. Actual [aml:/tmp/aml-BMOL72], Expected [aml:tests/data/acpi/aarch64/virt/DSDT].
See source file tests/qtest/bios-tables-test.c for instructions on how to update expected files.
acpi-test: Warning! DSDT mismatch. Actual [asl:/tmp/asl-RNOL72.dsl, aml:/tmp/aml-BMOL72], Expected [asl:/tmp/asl-ZVQL72.dsl, aml:tests/data/acpi/aarch64/virt/DS
DT].
```

Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
---

Notes:
    Changes since v3: 1. Add Reviewed-by from Sunil V L <sunilvl@ventanamicro.com>
                      2. Explicitly add "-serial stdio" to pass DSDT assert

 hw/arm/virt-acpi-build.c       | 15 +++++++++------
 hw/riscv/virt-acpi-build.c     |  7 +++++--
 include/system/system.h        |  2 ++
 system/vl.c                    |  5 +++++
 tests/qtest/bios-tables-test.c |  5 +++--
 5 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
index d77d16cbd3..c26aedb1b1 100644
--- a/hw/arm/virt-acpi-build.c
+++ b/hw/arm/virt-acpi-build.c
@@ -59,6 +59,7 @@
 #include "hw/acpi/viot.h"
 #include "hw/virtio/virtio-acpi.h"
 #include "target/arm/multiprocessing.h"
+#include "system/system.h"
 
 #define ARM_SPI_BASE 32
 
@@ -821,11 +822,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
      */
     scope = aml_scope("\\_SB");
     acpi_dsdt_add_cpus(scope, vms);
-    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
-                       (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
-    if (vms->second_ns_uart_present) {
-        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
-                           (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
+    if (serial_exist()) {
+        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
+                           (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
+        if (vms->second_ns_uart_present) {
+            acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
+                               (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
+        }
     }
     if (vmc->acpi_expose_flash) {
         acpi_dsdt_add_flash(scope, &memmap[VIRT_FLASH]);
@@ -937,7 +940,7 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
 
     acpi_add_table(table_offsets, tables_blob);
 
-    if (ms->acpi_spcr_enabled) {
+    if (ms->acpi_spcr_enabled && serial_exist()) {
         spcr_setup(tables_blob, tables->linker, vms);
     }
 
diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
index ee1416d264..80bf3c3cec 100644
--- a/hw/riscv/virt-acpi-build.c
+++ b/hw/riscv/virt-acpi-build.c
@@ -39,6 +39,7 @@
 #include "qapi/error.h"
 #include "qemu/error-report.h"
 #include "system/reset.h"
+#include "system/system.h"
 
 #define ACPI_BUILD_TABLE_SIZE             0x20000
 #define ACPI_BUILD_INTC_ID(socket, index) ((socket << 24) | (index))
@@ -474,7 +475,9 @@ static void build_dsdt(GArray *table_data,
                                  memmap[VIRT_APLIC_S].size, "RSCV0002");
     }
 
-    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
+    if (serial_exist())
+        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
+
     if (virt_is_iommu_sys_enabled(s)) {
         acpi_dsdt_add_iommu_sys(scope, &memmap[VIRT_IOMMU_SYS], IOMMU_SYS_IRQ);
     }
@@ -895,7 +898,7 @@ static void virt_acpi_build(RISCVVirtState *s, AcpiBuildTables *tables)
 
     acpi_add_table(table_offsets, tables_blob);
 
-    if (ms->acpi_spcr_enabled) {
+    if (ms->acpi_spcr_enabled && serial_exist()) {
         spcr_setup(tables_blob, tables->linker, s);
     }
 
diff --git a/include/system/system.h b/include/system/system.h
index a7effe7dfd..ca1af38432 100644
--- a/include/system/system.h
+++ b/include/system/system.h
@@ -75,6 +75,8 @@ extern unsigned int nb_prom_envs;
 /* Return the Chardev for serial port i, or NULL if none */
 Chardev *serial_hd(int i);
 
+bool serial_exist(void);
+
 /* parallel ports */
 
 #define MAX_PARALLEL_PORTS 3
diff --git a/system/vl.c b/system/vl.c
index fd402b8ff8..e340ee3a95 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -1485,6 +1485,11 @@ Chardev *serial_hd(int i)
     return NULL;
 }
 
+bool serial_exist(void)
+{
+    return serial_hd(0) ? true : false;
+}
+
 static bool parallel_parse(const char *devname, Error **errp)
 {
     static int index = 0;
diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
index 44de152a36..452566fa86 100644
--- a/tests/qtest/bios-tables-test.c
+++ b/tests/qtest/bios-tables-test.c
@@ -824,10 +824,11 @@ static char *test_acpi_create_args(test_data *data, const char *params)
         /*
          * TODO: convert '-drive if=pflash' to new syntax (see e33763be7cd3)
          * when arm/virt boad starts to support it.
+         * NOTE: Explicitly add "-serial stdio" to enable uart in DSDT.
          */
         if (data->cd) {
             args = g_strdup_printf("-machine %s%s %s -accel tcg "
-                "-nodefaults -nographic "
+                "-nodefaults -serial stdio -nographic "
                 "-drive if=pflash,format=raw,file=%s,readonly=on "
                 "-drive if=pflash,format=raw,file=%s,snapshot=on -cdrom %s %s",
                 data->machine, data->machine_param ?: "",
@@ -835,7 +836,7 @@ static char *test_acpi_create_args(test_data *data, const char *params)
                 data->uefi_fl1, data->uefi_fl2, data->cd, params ? params : "");
         } else {
             args = g_strdup_printf("-machine %s%s %s -accel tcg "
-                "-nodefaults -nographic "
+                "-nodefaults -serial stdio -nographic "
                 "-drive if=pflash,format=raw,file=%s,readonly=on "
                 "-drive if=pflash,format=raw,file=%s,snapshot=on %s",
                 data->machine, data->machine_param ?: "",
-- 
2.49.0


Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Michael S. Tsirkin 5 months, 1 week ago
On Wed, May 28, 2025 at 06:53:38PM +0800, Li Chen wrote:
> From: Li Chen <chenl311@chinatelecom.cn>
> 
> The virt machines always instantiate a PL011/16550 at UART0 and
> describe it in ACPI (DSDT device node plus optional SPCR table).  When
> the command line contains “-serial none” there is no backend attached to
> that UART, yet the guest still discovers it via ACPI and may try to use
> it as a console, causing unexpected results.
> 
> And also explicitly add "-serial stdio" in bios-tables-test.c to allow
> serial device creation, otherwise DSDT assert would get failure because
> "-nodefaults" will not create uart device by default:
> 
> ```
> stderr:
> acpi-test: Warning! DSDT binary file mismatch. Actual [aml:/tmp/aml-BMOL72], Expected [aml:tests/data/acpi/aarch64/virt/DSDT].
> See source file tests/qtest/bios-tables-test.c for instructions on how to update expected files.
> acpi-test: Warning! DSDT mismatch. Actual [asl:/tmp/asl-RNOL72.dsl, aml:/tmp/aml-BMOL72], Expected [asl:/tmp/asl-ZVQL72.dsl, aml:tests/data/acpi/aarch64/virt/DS
> DT].
> ```
> 
> Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
> Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>


will need to be rebased updating loongarch too, now.


> ---
> 
> Notes:
>     Changes since v3: 1. Add Reviewed-by from Sunil V L <sunilvl@ventanamicro.com>
>                       2. Explicitly add "-serial stdio" to pass DSDT assert
> 
>  hw/arm/virt-acpi-build.c       | 15 +++++++++------
>  hw/riscv/virt-acpi-build.c     |  7 +++++--
>  include/system/system.h        |  2 ++
>  system/vl.c                    |  5 +++++
>  tests/qtest/bios-tables-test.c |  5 +++--
>  5 files changed, 24 insertions(+), 10 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index d77d16cbd3..c26aedb1b1 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -59,6 +59,7 @@
>  #include "hw/acpi/viot.h"
>  #include "hw/virtio/virtio-acpi.h"
>  #include "target/arm/multiprocessing.h"
> +#include "system/system.h"
>  
>  #define ARM_SPI_BASE 32
>  
> @@ -821,11 +822,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
>       */
>      scope = aml_scope("\\_SB");
>      acpi_dsdt_add_cpus(scope, vms);
> -    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
> -                       (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
> -    if (vms->second_ns_uart_present) {
> -        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
> -                           (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
> +    if (serial_exist()) {
> +        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
> +                           (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
> +        if (vms->second_ns_uart_present) {
> +            acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
> +                               (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
> +        }
>      }
>      if (vmc->acpi_expose_flash) {
>          acpi_dsdt_add_flash(scope, &memmap[VIRT_FLASH]);
> @@ -937,7 +940,7 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
>  
>      acpi_add_table(table_offsets, tables_blob);
>  
> -    if (ms->acpi_spcr_enabled) {
> +    if (ms->acpi_spcr_enabled && serial_exist()) {
>          spcr_setup(tables_blob, tables->linker, vms);
>      }
>  
> diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
> index ee1416d264..80bf3c3cec 100644
> --- a/hw/riscv/virt-acpi-build.c
> +++ b/hw/riscv/virt-acpi-build.c
> @@ -39,6 +39,7 @@
>  #include "qapi/error.h"
>  #include "qemu/error-report.h"
>  #include "system/reset.h"
> +#include "system/system.h"
>  
>  #define ACPI_BUILD_TABLE_SIZE             0x20000
>  #define ACPI_BUILD_INTC_ID(socket, index) ((socket << 24) | (index))
> @@ -474,7 +475,9 @@ static void build_dsdt(GArray *table_data,
>                                   memmap[VIRT_APLIC_S].size, "RSCV0002");
>      }
>  
> -    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
> +    if (serial_exist())
> +        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
> +

coding style violation

>      if (virt_is_iommu_sys_enabled(s)) {
>          acpi_dsdt_add_iommu_sys(scope, &memmap[VIRT_IOMMU_SYS], IOMMU_SYS_IRQ);
>      }
> @@ -895,7 +898,7 @@ static void virt_acpi_build(RISCVVirtState *s, AcpiBuildTables *tables)
>  
>      acpi_add_table(table_offsets, tables_blob);
>  
> -    if (ms->acpi_spcr_enabled) {
> +    if (ms->acpi_spcr_enabled && serial_exist()) {
>          spcr_setup(tables_blob, tables->linker, s);
>      }
>  
> diff --git a/include/system/system.h b/include/system/system.h
> index a7effe7dfd..ca1af38432 100644
> --- a/include/system/system.h
> +++ b/include/system/system.h
> @@ -75,6 +75,8 @@ extern unsigned int nb_prom_envs;
>  /* Return the Chardev for serial port i, or NULL if none */
>  Chardev *serial_hd(int i);
>  
> +bool serial_exist(void);
> +
>  /* parallel ports */
>  
>  #define MAX_PARALLEL_PORTS 3
> diff --git a/system/vl.c b/system/vl.c
> index fd402b8ff8..e340ee3a95 100644
> --- a/system/vl.c
> +++ b/system/vl.c
> @@ -1485,6 +1485,11 @@ Chardev *serial_hd(int i)
>      return NULL;
>  }
>  
> +bool serial_exist(void)
> +{
> +    return serial_hd(0) ? true : false;
> +}
> +

serial_exists


>  static bool parallel_parse(const char *devname, Error **errp)
>  {
>      static int index = 0;
> diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
> index 44de152a36..452566fa86 100644
> --- a/tests/qtest/bios-tables-test.c
> +++ b/tests/qtest/bios-tables-test.c
> @@ -824,10 +824,11 @@ static char *test_acpi_create_args(test_data *data, const char *params)
>          /*
>           * TODO: convert '-drive if=pflash' to new syntax (see e33763be7cd3)
>           * when arm/virt boad starts to support it.
> +         * NOTE: Explicitly add "-serial stdio" to enable uart in DSDT.
>           */
>          if (data->cd) {
>              args = g_strdup_printf("-machine %s%s %s -accel tcg "
> -                "-nodefaults -nographic "
> +                "-nodefaults -serial stdio -nographic "
>                  "-drive if=pflash,format=raw,file=%s,readonly=on "
>                  "-drive if=pflash,format=raw,file=%s,snapshot=on -cdrom %s %s",
>                  data->machine, data->machine_param ?: "",
> @@ -835,7 +836,7 @@ static char *test_acpi_create_args(test_data *data, const char *params)
>                  data->uefi_fl1, data->uefi_fl2, data->cd, params ? params : "");
>          } else {
>              args = g_strdup_printf("-machine %s%s %s -accel tcg "
> -                "-nodefaults -nographic "
> +                "-nodefaults -serial stdio -nographic "
>                  "-drive if=pflash,format=raw,file=%s,readonly=on "
>                  "-drive if=pflash,format=raw,file=%s,snapshot=on %s",
>                  data->machine, data->machine_param ?: "",




> -- 
> 2.49.0


Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 5 months ago
Hi Michael,

Thanks for your kind review! All issues below have been fixed in v5:
https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762

 ---- On Tue, 15 Jul 2025 02:45:31 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > On Wed, May 28, 2025 at 06:53:38PM +0800, Li Chen wrote:
 > > From: Li Chen <chenl311@chinatelecom.cn>
 > > 
 > > The virt machines always instantiate a PL011/16550 at UART0 and
 > > describe it in ACPI (DSDT device node plus optional SPCR table).  When
 > > the command line contains “-serial none” there is no backend attached to
 > > that UART, yet the guest still discovers it via ACPI and may try to use
 > > it as a console, causing unexpected results.
 > > 
 > > And also explicitly add "-serial stdio" in bios-tables-test.c to allow
 > > serial device creation, otherwise DSDT assert would get failure because
 > > "-nodefaults" will not create uart device by default:
 > > 
 > > ```
 > > stderr:
 > > acpi-test: Warning! DSDT binary file mismatch. Actual [aml:/tmp/aml-BMOL72], Expected [aml:tests/data/acpi/aarch64/virt/DSDT].
 > > See source file tests/qtest/bios-tables-test.c for instructions on how to update expected files.
 > > acpi-test: Warning! DSDT mismatch. Actual [asl:/tmp/asl-RNOL72.dsl, aml:/tmp/aml-BMOL72], Expected [asl:/tmp/asl-ZVQL72.dsl, aml:tests/data/acpi/aarch64/virt/DS
 > > DT].
 > > ```
 > > 
 > > Suggested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
 > > Signed-off-by: Li Chen <chenl311@chinatelecom.cn>
 > > Reviewed-by: Sunil V L <sunilvl@ventanamicro.com>
 > 
 > 
 > will need to be rebased updating loongarch too, now.
 > 
 > 
 > > ---
 > > 
 > > Notes:
 > >     Changes since v3: 1. Add Reviewed-by from Sunil V L <sunilvl@ventanamicro.com>
 > >                       2. Explicitly add "-serial stdio" to pass DSDT assert
 > > 
 > >  hw/arm/virt-acpi-build.c       | 15 +++++++++------
 > >  hw/riscv/virt-acpi-build.c     |  7 +++++--
 > >  include/system/system.h        |  2 ++
 > >  system/vl.c                    |  5 +++++
 > >  tests/qtest/bios-tables-test.c |  5 +++--
 > >  5 files changed, 24 insertions(+), 10 deletions(-)
 > > 
 > > diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
 > > index d77d16cbd3..c26aedb1b1 100644
 > > --- a/hw/arm/virt-acpi-build.c
 > > +++ b/hw/arm/virt-acpi-build.c
 > > @@ -59,6 +59,7 @@
 > >  #include "hw/acpi/viot.h"
 > >  #include "hw/virtio/virtio-acpi.h"
 > >  #include "target/arm/multiprocessing.h"
 > > +#include "system/system.h"
 > >  
 > >  #define ARM_SPI_BASE 32
 > >  
 > > @@ -821,11 +822,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker, VirtMachineState *vms)
 > >       */
 > >      scope = aml_scope("\\_SB");
 > >      acpi_dsdt_add_cpus(scope, vms);
 > > -    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
 > > -                       (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
 > > -    if (vms->second_ns_uart_present) {
 > > -        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
 > > -                           (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
 > > +    if (serial_exist()) {
 > > +        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0],
 > > +                           (irqmap[VIRT_UART0] + ARM_SPI_BASE), 0);
 > > +        if (vms->second_ns_uart_present) {
 > > +            acpi_dsdt_add_uart(scope, &memmap[VIRT_UART1],
 > > +                               (irqmap[VIRT_UART1] + ARM_SPI_BASE), 1);
 > > +        }
 > >      }
 > >      if (vmc->acpi_expose_flash) {
 > >          acpi_dsdt_add_flash(scope, &memmap[VIRT_FLASH]);
 > > @@ -937,7 +940,7 @@ void virt_acpi_build(VirtMachineState *vms, AcpiBuildTables *tables)
 > >  
 > >      acpi_add_table(table_offsets, tables_blob);
 > >  
 > > -    if (ms->acpi_spcr_enabled) {
 > > +    if (ms->acpi_spcr_enabled && serial_exist()) {
 > >          spcr_setup(tables_blob, tables->linker, vms);
 > >      }
 > >  
 > > diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
 > > index ee1416d264..80bf3c3cec 100644
 > > --- a/hw/riscv/virt-acpi-build.c
 > > +++ b/hw/riscv/virt-acpi-build.c
 > > @@ -39,6 +39,7 @@
 > >  #include "qapi/error.h"
 > >  #include "qemu/error-report.h"
 > >  #include "system/reset.h"
 > > +#include "system/system.h"
 > >  
 > >  #define ACPI_BUILD_TABLE_SIZE             0x20000
 > >  #define ACPI_BUILD_INTC_ID(socket, index) ((socket << 24) | (index))
 > > @@ -474,7 +475,9 @@ static void build_dsdt(GArray *table_data,
 > >                                   memmap[VIRT_APLIC_S].size, "RSCV0002");
 > >      }
 > >  
 > > -    acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
 > > +    if (serial_exist())
 > > +        acpi_dsdt_add_uart(scope, &memmap[VIRT_UART0], UART0_IRQ);
 > > +
 > 
 > coding style violation
 > 
 > >      if (virt_is_iommu_sys_enabled(s)) {
 > >          acpi_dsdt_add_iommu_sys(scope, &memmap[VIRT_IOMMU_SYS], IOMMU_SYS_IRQ);
 > >      }
 > > @@ -895,7 +898,7 @@ static void virt_acpi_build(RISCVVirtState *s, AcpiBuildTables *tables)
 > >  
 > >      acpi_add_table(table_offsets, tables_blob);
 > >  
 > > -    if (ms->acpi_spcr_enabled) {
 > > +    if (ms->acpi_spcr_enabled && serial_exist()) {
 > >          spcr_setup(tables_blob, tables->linker, s);
 > >      }
 > >  
 > > diff --git a/include/system/system.h b/include/system/system.h
 > > index a7effe7dfd..ca1af38432 100644
 > > --- a/include/system/system.h
 > > +++ b/include/system/system.h
 > > @@ -75,6 +75,8 @@ extern unsigned int nb_prom_envs;
 > >  /* Return the Chardev for serial port i, or NULL if none */
 > >  Chardev *serial_hd(int i);
 > >  
 > > +bool serial_exist(void);
 > > +
 > >  /* parallel ports */
 > >  
 > >  #define MAX_PARALLEL_PORTS 3
 > > diff --git a/system/vl.c b/system/vl.c
 > > index fd402b8ff8..e340ee3a95 100644
 > > --- a/system/vl.c
 > > +++ b/system/vl.c
 > > @@ -1485,6 +1485,11 @@ Chardev *serial_hd(int i)
 > >      return NULL;
 > >  }
 > >  
 > > +bool serial_exist(void)
 > > +{
 > > +    return serial_hd(0) ? true : false;
 > > +}
 > > +
 > 
 > serial_exists
 > 
 > 
 > >  static bool parallel_parse(const char *devname, Error **errp)
 > >  {
 > >      static int index = 0;
 > > diff --git a/tests/qtest/bios-tables-test.c b/tests/qtest/bios-tables-test.c
 > > index 44de152a36..452566fa86 100644
 > > --- a/tests/qtest/bios-tables-test.c
 > > +++ b/tests/qtest/bios-tables-test.c
 > > @@ -824,10 +824,11 @@ static char *test_acpi_create_args(test_data *data, const char *params)
 > >          /*
 > >           * TODO: convert '-drive if=pflash' to new syntax (see e33763be7cd3)
 > >           * when arm/virt boad starts to support it.
 > > +         * NOTE: Explicitly add "-serial stdio" to enable uart in DSDT.
 > >           */
 > >          if (data->cd) {
 > >              args = g_strdup_printf("-machine %s%s %s -accel tcg "
 > > -                "-nodefaults -nographic "
 > > +                "-nodefaults -serial stdio -nographic "
 > >                  "-drive if=pflash,format=raw,file=%s,readonly=on "
 > >                  "-drive if=pflash,format=raw,file=%s,snapshot=on -cdrom %s %s",
 > >                  data->machine, data->machine_param ?: "",
 > > @@ -835,7 +836,7 @@ static char *test_acpi_create_args(test_data *data, const char *params)
 > >                  data->uefi_fl1, data->uefi_fl2, data->cd, params ? params : "");
 > >          } else {
 > >              args = g_strdup_printf("-machine %s%s %s -accel tcg "
 > > -                "-nodefaults -nographic "
 > > +                "-nodefaults -serial stdio -nographic "
 > >                  "-drive if=pflash,format=raw,file=%s,readonly=on "
 > >                  "-drive if=pflash,format=raw,file=%s,snapshot=on %s",
 > >                  data->machine, data->machine_param ?: "",
 > 
 > 
 > 
 > 
 > > -- 
 > > 2.49.0
 > 
 > 
Regards,

Li​
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Michael S. Tsirkin 5 months ago
On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
> Hi Michael,
> 
> Thanks for your kind review! All issues below have been fixed in v5:
> https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762

Past soft freeze now: I tagged this but pls remind me after the release
to help make sure it's not lost.
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 5 months ago
Hi Michael,

 ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
 > > Hi Michael,
 > > 
 > > Thanks for your kind review! All issues below have been fixed in v5:
 > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
 > 
 > Past soft freeze now: I tagged this but pls remind me after the release
 > to help make sure it's not lost.
 > 

Ok.

Regards,
Li​
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 3 months ago
Hi Michael,

 ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
 > Hi Michael,
 > 
 >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
 >  > > Hi Michael,
 >  > > 
 >  > > Thanks for your kind review! All issues below have been fixed in v5:
 >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
 >  > 
 >  > Past soft freeze now: I tagged this but pls remind me after the release
 >  > to help make sure it's not lost.
 
Gentle reminder: This patch is still missing from the latest master branch, but can apply without
any conflict. Can it be included in 10.2?

Regards,
Li.
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 1 week, 1 day ago
Hi Michael,

 ---- On Fri, 19 Sep 2025 07:38:56 +0800  Li Chen <me@linux.beauty> wrote --- 
 > Hi Michael,
 > 
 >  ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
 >  > Hi Michael,
 >  > 
 >  >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 >  >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
 >  >  > > Hi Michael,
 >  >  > > 
 >  >  > > Thanks for your kind review! All issues below have been fixed in v5:
 >  >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
 >  >  > 
 >  >  > Past soft freeze now: I tagged this but pls remind me after the release
 >  >  > to help make sure it's not lost.
 >  
 > Gentle reminder: This patch is still missing from the latest master branch, but can apply without
 > any conflict. Can it be included in 10.2?
 > 
 > Regards,
 > Li.
 > 
 > 

Sorry for bothering again. But I'm still unable to find this patch in the latest master branch, though it applies without conflicts now. 

Could it be merged now?

Regards,
Li​
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Michael S. Tsirkin 1 week, 1 day ago
On Wed, Dec 10, 2025 at 08:23:21PM +0800, Li Chen wrote:
> Hi Michael,
> 
>  ---- On Fri, 19 Sep 2025 07:38:56 +0800  Li Chen <me@linux.beauty> wrote --- 
>  > Hi Michael,
>  > 
>  >  ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
>  >  > Hi Michael,
>  >  > 
>  >  >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
>  >  >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
>  >  >  > > Hi Michael,
>  >  >  > > 
>  >  >  > > Thanks for your kind review! All issues below have been fixed in v5:
>  >  >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
>  >  >  > 
>  >  >  > Past soft freeze now: I tagged this but pls remind me after the release
>  >  >  > to help make sure it's not lost.
>  >  
>  > Gentle reminder: This patch is still missing from the latest master branch, but can apply without
>  > any conflict. Can it be included in 10.2?
>  > 
>  > Regards,
>  > Li.
>  > 
>  > 
> 
> Sorry for bothering again. But I'm still unable to find this patch in the latest master branch, though it applies without conflicts now. 
> 
> Could it be merged now?
> 
> Regards,
> Li​

you still need to update loongarch, I think. otherwise these tests will
fail.

-- 
MST


Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 1 week, 1 day ago
Hi Tsirkin,

 ---- On Wed, 10 Dec 2025 20:53:01 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > On Wed, Dec 10, 2025 at 08:23:21PM +0800, Li Chen wrote:
 > > Hi Michael,
 > > 
 > >  ---- On Fri, 19 Sep 2025 07:38:56 +0800  Li Chen <me@linux.beauty> wrote --- 
 > >  > Hi Michael,
 > >  > 
 > >  >  ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
 > >  >  > Hi Michael,
 > >  >  > 
 > >  >  >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > >  >  >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
 > >  >  >  > > Hi Michael,
 > >  >  >  > > 
 > >  >  >  > > Thanks for your kind review! All issues below have been fixed in v5:
 > >  >  >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
 > >  >  >  > 
 > >  >  >  > Past soft freeze now: I tagged this but pls remind me after the release
 > >  >  >  > to help make sure it's not lost.
 > >  >  
 > >  > Gentle reminder: This patch is still missing from the latest master branch, but can apply without
 > >  > any conflict. Can it be included in 10.2?
 > >  > 
 > >  > Regards,
 > >  > Li.
 > >  > 
 > >  > 
 > > 
 > > Sorry for bothering again. But I'm still unable to find this patch in the latest master branch, though it applies without conflicts now. 
 > > 
 > > Could it be merged now?
 > > 
 > > Regards,
 > > Li​
 > 
 > you still need to update loongarch, I think. otherwise these tests will
 > fail.

Yes, it seems that tap stdout is polluted by serial stdio.

I'll address the stdout pollution from -serial stdio by redirecting serial output to /dev/null using -serial null in the next version. 
This will still create the serial device but prevent it from writing to the console.

Regards,

Li​
Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Michael S. Tsirkin 1 week ago
On Thu, Dec 11, 2025 at 08:03:05AM +0800, Li Chen wrote:
> Hi Tsirkin,
> 
>  ---- On Wed, 10 Dec 2025 20:53:01 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
>  > On Wed, Dec 10, 2025 at 08:23:21PM +0800, Li Chen wrote:
>  > > Hi Michael,
>  > > 
>  > >  ---- On Fri, 19 Sep 2025 07:38:56 +0800  Li Chen <me@linux.beauty> wrote --- 
>  > >  > Hi Michael,
>  > >  > 
>  > >  >  ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
>  > >  >  > Hi Michael,
>  > >  >  > 
>  > >  >  >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
>  > >  >  >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
>  > >  >  >  > > Hi Michael,
>  > >  >  >  > > 
>  > >  >  >  > > Thanks for your kind review! All issues below have been fixed in v5:
>  > >  >  >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
>  > >  >  >  > 
>  > >  >  >  > Past soft freeze now: I tagged this but pls remind me after the release
>  > >  >  >  > to help make sure it's not lost.
>  > >  >  
>  > >  > Gentle reminder: This patch is still missing from the latest master branch, but can apply without
>  > >  > any conflict. Can it be included in 10.2?
>  > >  > 
>  > >  > Regards,
>  > >  > Li.
>  > >  > 
>  > >  > 
>  > > 
>  > > Sorry for bothering again. But I'm still unable to find this patch in the latest master branch, though it applies without conflicts now. 
>  > > 
>  > > Could it be merged now?
>  > > 
>  > > Regards,
>  > > Li​
>  > 
>  > you still need to update loongarch, I think. otherwise these tests will
>  > fail.
> 
> Yes, it seems that tap stdout is polluted by serial stdio.
> 
> I'll address the stdout pollution from -serial stdio by redirecting serial output to /dev/null using -serial null in the next version. 
> This will still create the serial device but prevent it from writing to the console.
> 
> Regards,
> 
> Li​

I don't know about that, what I meant is that loongaarch also has SPCR
so it's expected tables have to be updated.

-- 
MST


Re: [PATCH REPOST v4 4/4] acpi/virt: suppress UART device & SPCR when guest has no serial hardware
Posted by Li Chen 1 week ago
Hi Michael,

 ---- On Thu, 11 Dec 2025 15:43:45 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > On Thu, Dec 11, 2025 at 08:03:05AM +0800, Li Chen wrote:
 > > Hi Tsirkin,
 > > 
 > >  ---- On Wed, 10 Dec 2025 20:53:01 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > >  > On Wed, Dec 10, 2025 at 08:23:21PM +0800, Li Chen wrote:
 > >  > > Hi Michael,
 > >  > > 
 > >  > >  ---- On Fri, 19 Sep 2025 07:38:56 +0800  Li Chen <me@linux.beauty> wrote --- 
 > >  > >  > Hi Michael,
 > >  > >  > 
 > >  > >  >  ---- On Wed, 16 Jul 2025 19:59:14 +0800  Li Chen <me@linux.beauty> wrote --- 
 > >  > >  >  > Hi Michael,
 > >  > >  >  > 
 > >  > >  >  >  ---- On Wed, 16 Jul 2025 19:42:42 +0800  Michael S. Tsirkin <mst@redhat.com> wrote --- 
 > >  > >  >  >  > On Wed, Jul 16, 2025 at 07:41:11PM +0800, Li Chen wrote:
 > >  > >  >  >  > > Hi Michael,
 > >  > >  >  >  > > 
 > >  > >  >  >  > > Thanks for your kind review! All issues below have been fixed in v5:
 > >  > >  >  >  > > https://lore.kernel.org/qemu-devel/20250716111959.404917-5-me@linux.beauty/T/#m696cee9a95646add1b74b866c3d6761aa4c5c762
 > >  > >  >  >  > 
 > >  > >  >  >  > Past soft freeze now: I tagged this but pls remind me after the release
 > >  > >  >  >  > to help make sure it's not lost.
 > >  > >  >  
 > >  > >  > Gentle reminder: This patch is still missing from the latest master branch, but can apply without
 > >  > >  > any conflict. Can it be included in 10.2?
 > >  > >  > 
 > >  > >  > Regards,
 > >  > >  > Li.
 > >  > >  > 
 > >  > >  > 
 > >  > > 
 > >  > > Sorry for bothering again. But I'm still unable to find this patch in the latest master branch, though it applies without conflicts now. 
 > >  > > 
 > >  > > Could it be merged now?
 > >  > > 
 > >  > > Regards,
 > >  > > Li​
 > >  > 
 > >  > you still need to update loongarch, I think. otherwise these tests will
 > >  > fail.
 > > 
 > > Yes, it seems that tap stdout is polluted by serial stdio.
 > > 
 > > I'll address the stdout pollution from -serial stdio by redirecting serial output to /dev/null using -serial null in the next version. 
 > > This will still create the serial device but prevent it from writing to the console.
 > > 
 > > Regards,
 > > 
 > > Li​
 > 
 > I don't know about that, what I meant is that loongaarch also has SPCR
 > so it's expected tables have to be updated.

My apologies, I misunderstood your previous comment. I just found I already added LoongArch support in v5 [1] months ago. I've now fixed the tap 
parsing error and submitted v6 of the patch [2]. And now all tests can pass.

[1]: https://patchew.org/QEMU/20250716111959.404917-1-me@linux.beauty/20250716111959.404917-5-me@linux.beauty/
[2]: https://lore.kernel.org/qemu-devel/20251211102025.873506-1-me@linux.beauty/T/#u

Regards,

Li​