KVM: selftests: Test IPI to halted vCPU in xAPIC while backing page moves

When a guest is using xAPIC KVM allocates a backing page for the required
EPT entry for the APIC access address set in the VMCS. If mm decides to
move that page the KVM mmu notifier will update the VMCS with the new
HPA. This test induces a page move to test that APIC access continues to
work correctly. It is a directed test for
commit e649b3f0 "KVM: x86: Fix APIC page invalidation race".

Tested: ran for 1 hour on a skylake, migrating backing page every 1ms

Depends on patch "selftests: kvm: Add exception handling to selftests"
from aaronlewis@google.com that has not yet been queued.
Signed-off-by: Peter Shier <pshier@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Ricardo Koller <ricarkol@google.com>
Message-Id: <20201105223823.850068-1-pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/.gitignore

@@ -24,6 +24,7 @@
 /x86_64/vmx_preemption_timer_test
 /x86_64/vmx_set_nested_state_test
 /x86_64/vmx_tsc_adjust_test
+/x86_64/xapic_ipi_test
 /x86_64/xss_msr_test
 /demand_paging_test
 /dirty_log_test

tools/testing/selftests/kvm/Makefile

@@ -56,6 +56,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_close_while_nested_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_dirty_log_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_set_nested_state_test
 TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
+TEST_GEN_PROGS_x86_64 += x86_64/xapic_ipi_test
 TEST_GEN_PROGS_x86_64 += x86_64/xss_msr_test
 TEST_GEN_PROGS_x86_64 += x86_64/debug_regs
 TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test

tools/testing/selftests/kvm/include/x86_64/processor.h

@@ -406,8 +406,27 @@ uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
 #define X86_CR0_CD          (1UL<<30) /* Cache Disable */
 #define X86_CR0_PG          (1UL<<31) /* Paging */
 
+#define APIC_DEFAULT_GPA		0xfee00000ULL
+
+/* APIC base address MSR and fields */
+#define MSR_IA32_APICBASE		0x0000001b
+#define MSR_IA32_APICBASE_BSP		(1<<8)
+#define MSR_IA32_APICBASE_EXTD		(1<<10)
+#define MSR_IA32_APICBASE_ENABLE	(1<<11)
+#define MSR_IA32_APICBASE_BASE		(0xfffff<<12)
+#define		GET_APIC_BASE(x)	(((x) >> 12) << 12)
+
 #define APIC_BASE_MSR	0x800
 #define X2APIC_ENABLE	(1UL << 10)
+#define	APIC_ID		0x20
+#define	APIC_LVR	0x30
+#define		GET_APIC_ID_FIELD(x)	(((x) >> 24) & 0xFF)
+#define	APIC_TASKPRI	0x80
+#define	APIC_PROCPRI	0xA0
+#define	APIC_EOI	0xB0
+#define	APIC_SPIV	0xF0
+#define		APIC_SPIV_FOCUS_DISABLED	(1 << 9)
+#define		APIC_SPIV_APIC_ENABLED		(1 << 8)
 #define	APIC_ICR	0x300
 #define		APIC_DEST_SELF		0x40000
 #define		APIC_DEST_ALLINC	0x80000
@@ -432,6 +451,7 @@ uint64_t kvm_hypercall(uint64_t nr, uint64_t a0, uint64_t a1, uint64_t a2,
 #define		APIC_DM_EXTINT		0x00700
 #define		APIC_VECTOR_MASK	0x000FF
 #define	APIC_ICR2	0x310
+#define		SET_APIC_DEST_FIELD(x)	((x) << 24)
 
 /* VMX_EPT_VPID_CAP bits */
 #define VMX_EPT_VPID_CAP_AD_BITS       (1ULL << 21)