From 7bb1f124413891bc5d2187f12cd19da6e794904b Mon Sep 17 00:00:00 2001 From: Xiaoyao Li Date: Wed, 3 Apr 2024 10:59:53 -0400 Subject: [PATCH 010/100] hw/i386/acpi: Set PCAT_COMPAT bit only when pic is not disabled RH-Author: Paolo Bonzini RH-MergeRequest: 245: SEV-SNP support RH-Jira: RHEL-39544 RH-Acked-by: Thomas Huth RH-Acked-by: Bandan Das RH-Acked-by: Vitaly Kuznetsov RH-Commit: [10/91] 62110e4bf52cb3e106c8d2a902bbd31548beba00 (bonzini/rhel-qemu-kvm) 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. The PIC probe should then print: [ 0.155970] Using NULL legacy PIC However, no such log printed in guest kernel unless PCAT_COMPAT is cleared. Signed-off-by: Xiaoyao Li Message-ID: <20240403145953.3082491-1-xiaoyao.li@intel.com> Signed-off-by: Paolo Bonzini (cherry picked from commit 292dd287e78e0cbafde9d1522c729349d132d844) Signed-off-by: Paolo Bonzini --- 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 20f19269da..0cc2919bb8 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, 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); -- 2.39.3