From: Nadav Amit <nadav.amit@xxxxxxxxx>
After the APIC is reset, some of its registers might be reset. As the
SDM says: "When IA32_APIC_BASE[11] is set to 0, prior initialization to
the APIC may be lost and the APIC may return to the state described in
Section 10.4.7.1". The SDM also says that after APIC reset "the
spurious-interrupt vector register is initialized to 000000FFH". This
means that after the APIC is reset it needs to be software-enabled
through the SPIV.
This is done one occasion, but there are (at least) two occasions that
do not software-enable the APIC after reset (__test_apic_id() and main()
in vmx.c).
Move APIC SPIV reinitialization into reset_apic(). Remove SPIV settings
which are unnecessary after reset_apic() is modified.
Cc: Sean Christopherson <sean.j.christopherson@xxxxxxxxx>
Signed-off-by: Nadav Amit <nadav.amit@xxxxxxxxx>
---
lib/x86/apic.c | 1 +
x86/apic.c | 1 -
2 files changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/x86/apic.c b/lib/x86/apic.c
index 2aeffbd..4e7d43c 100644
--- a/lib/x86/apic.c
+++ b/lib/x86/apic.c
@@ -161,6 +161,7 @@ void reset_apic(void)
{
disable_apic();
wrmsr(MSR_IA32_APICBASE, rdmsr(MSR_IA32_APICBASE) | APIC_EN);
+ apic_write(APIC_SPIV, 0x1ff);
}
u32 ioapic_read_reg(unsigned reg)
diff --git a/x86/apic.c b/x86/apic.c
index 3eff588..7ef4a27 100644
--- a/x86/apic.c
+++ b/x86/apic.c
@@ -148,7 +148,6 @@ static void test_apic_disable(void)
verify_disabled_apic_mmio();
reset_apic();
- apic_write(APIC_SPIV, 0x1ff);
report("Local apic enabled in xAPIC mode",
(rdmsr(MSR_IA32_APICBASE) & (APIC_EN | APIC_EXTD)) == APIC_EN);
report("CPUID.1H:EDX.APIC[bit 9] is set", cpuid(1).d & (1 << 9));
--
2.17.1
