diff options
Diffstat (limited to 'tools/testing/selftests/kvm/lib/x86/apic.c')
| -rw-r--r-- | tools/testing/selftests/kvm/lib/x86/apic.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/x86/apic.c b/tools/testing/selftests/kvm/lib/x86/apic.c new file mode 100644 index 000000000000..89153a333e83 --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86/apic.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2021, Google LLC. + */ + +#include "apic.h" + +void apic_disable(void) +{ + wrmsr(MSR_IA32_APICBASE, + rdmsr(MSR_IA32_APICBASE) & + ~(MSR_IA32_APICBASE_ENABLE | MSR_IA32_APICBASE_EXTD)); +} + +void xapic_enable(void) +{ + uint64_t val = rdmsr(MSR_IA32_APICBASE); + + /* Per SDM: to enable xAPIC when in x2APIC must first disable APIC */ + if (val & MSR_IA32_APICBASE_EXTD) { + apic_disable(); + wrmsr(MSR_IA32_APICBASE, + rdmsr(MSR_IA32_APICBASE) | MSR_IA32_APICBASE_ENABLE); + } else if (!(val & MSR_IA32_APICBASE_ENABLE)) { + wrmsr(MSR_IA32_APICBASE, val | MSR_IA32_APICBASE_ENABLE); + } + + /* + * Per SDM: reset value of spurious interrupt vector register has the + * APIC software enabled bit=0. It must be enabled in addition to the + * enable bit in the MSR. + */ + val = xapic_read_reg(APIC_SPIV) | APIC_SPIV_APIC_ENABLED; + xapic_write_reg(APIC_SPIV, val); +} + +void x2apic_enable(void) +{ + wrmsr(MSR_IA32_APICBASE, rdmsr(MSR_IA32_APICBASE) | + MSR_IA32_APICBASE_ENABLE | MSR_IA32_APICBASE_EXTD); + x2apic_write_reg(APIC_SPIV, + x2apic_read_reg(APIC_SPIV) | APIC_SPIV_APIC_ENABLED); +} |