Re: [PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
On Mon, Apr 15, 2024 at 05:51:56AM -0400, Michael S. Tsirkin wrote: > On Mon, Apr 15, 2024 at 11:44:50AM +0200, Paolo Bonzini wrote: > > Queued, thanks. > > > > Paolo > > I actually had it queued too - it's not 9.0 material though. > If you queue it don't forget to tweak the commit log manually. oh and then you can add my Reviewed-by: Michael S. Tsirkin > -- > MST
Re: [PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
On Mon, Apr 15, 2024 at 11:44:50AM +0200, Paolo Bonzini wrote: > Queued, thanks. > > Paolo I actually had it queued too - it's not 9.0 material though. If you queue it don't forget to tweak the commit log manually. -- MST
Re: [PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
Queued, thanks. Paolo
Re: [PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
On 4/3/2024 11:12 PM, Igor Mammedov wrote:
On Wed, 3 Apr 2024 10:59:53 -0400
Xiaoyao Li wrote:
A value 1 of PCAT_COMPAT (bit 0) of MADT.Flags indicates that the system
also has a PC-AT-compatible dual-8259 setup, i.e., the PIC.
When PIC is not enabled (pic=off) for x86 machine, the PCAT_COMPAT bit
needs to be cleared. Otherwise, the guest thinks there is a present PIC.
Can you add to commit message reproducer (aka qemu CLI and relevant
logs/symptoms observed on guest side)?
When booting a VM with "-machine xx,pic=off", there is supposed to be no
PIC for the guest. When guest probes PIC, it should find nothing and log
of below should be printed:
[0.155970] Using NULL legacy PIC
However, the fact is that no such log printed in guest kernel, with the
VM created with "pic=off". This is because guest think there is a
present due to pcat_compat is reporte as 1 in MADT. See Linux code of
probe_8259A() in arch/x86/kernel/i8259.c
Signed-off-by: Xiaoyao Li
---
changes in v2:
- Clarify more in commit message;
---
hw/i386/acpi-common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/hw/i386/acpi-common.c b/hw/i386/acpi-common.c
index 20f19269da40..0cc2919bb851 100644
--- a/hw/i386/acpi-common.c
+++ b/hw/i386/acpi-common.c
@@ -107,7 +107,9 @@ void acpi_build_madt(GArray *table_data, BIOSLinker *linker,
acpi_table_begin(, table_data);
/* Local APIC Address */
build_append_int_noprefix(table_data, APIC_DEFAULT_ADDRESS, 4);
-build_append_int_noprefix(table_data, 1 /* PCAT_COMPAT */, 4); /* Flags */
+/* Flags. bit 0: PCAT_COMPAT */
+build_append_int_noprefix(table_data,
+ x86ms->pic != ON_OFF_AUTO_OFF ? 1 : 0 , 4);
for (i = 0; i < apic_ids->len; i++) {
pc_madt_cpu_entry(i, apic_ids, table_data, false);
Re: [PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
On Wed, 3 Apr 2024 10:59:53 -0400
Xiaoyao Li wrote:
> A value 1 of PCAT_COMPAT (bit 0) of MADT.Flags indicates that the system
> also has a PC-AT-compatible dual-8259 setup, i.e., the PIC.
>
> When PIC is not enabled (pic=off) for x86 machine, the PCAT_COMPAT bit
> needs to be cleared. Otherwise, the guest thinks there is a present PIC.
Can you add to commit message reproducer (aka qemu CLI and relevant
logs/symptoms observed on guest side)?
>
> Signed-off-by: Xiaoyao Li
> ---
> changes in v2:
> - Clarify more in commit message;
> ---
> hw/i386/acpi-common.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/acpi-common.c b/hw/i386/acpi-common.c
> index 20f19269da40..0cc2919bb851 100644
> --- a/hw/i386/acpi-common.c
> +++ b/hw/i386/acpi-common.c
> @@ -107,7 +107,9 @@ void acpi_build_madt(GArray *table_data, BIOSLinker
> *linker,
> acpi_table_begin(, table_data);
> /* Local APIC Address */
> build_append_int_noprefix(table_data, APIC_DEFAULT_ADDRESS, 4);
> -build_append_int_noprefix(table_data, 1 /* PCAT_COMPAT */, 4); /* Flags
> */
> +/* Flags. bit 0: PCAT_COMPAT */
> +build_append_int_noprefix(table_data,
> + x86ms->pic != ON_OFF_AUTO_OFF ? 1 : 0 , 4);
>
> for (i = 0; i < apic_ids->len; i++) {
> pc_madt_cpu_entry(i, apic_ids, table_data, false);
[PATCH v2] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled
A value 1 of PCAT_COMPAT (bit 0) of MADT.Flags indicates that the system
also has a PC-AT-compatible dual-8259 setup, i.e., the PIC.
When PIC is not enabled (pic=off) for x86 machine, the PCAT_COMPAT bit
needs to be cleared. Otherwise, the guest thinks there is a present PIC.
Signed-off-by: Xiaoyao Li
---
changes in v2:
- Clarify more in commit message;
---
hw/i386/acpi-common.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/hw/i386/acpi-common.c b/hw/i386/acpi-common.c
index 20f19269da40..0cc2919bb851 100644
--- a/hw/i386/acpi-common.c
+++ b/hw/i386/acpi-common.c
@@ -107,7 +107,9 @@ void acpi_build_madt(GArray *table_data, BIOSLinker *linker,
acpi_table_begin(, table_data);
/* Local APIC Address */
build_append_int_noprefix(table_data, APIC_DEFAULT_ADDRESS, 4);
-build_append_int_noprefix(table_data, 1 /* PCAT_COMPAT */, 4); /* Flags */
+/* Flags. bit 0: PCAT_COMPAT */
+build_append_int_noprefix(table_data,
+ x86ms->pic != ON_OFF_AUTO_OFF ? 1 : 0 , 4);
for (i = 0; i < apic_ids->len; i++) {
pc_madt_cpu_entry(i, apic_ids, table_data, false);
--
2.34.1
