[PATCH v3 2/4] KVM: arm64: selftests: Add vgic IIDR revision test

[David Woodhouse <dwmw2@infradead.org>]

From: David Woodhouse <dwmw@amazon.co.uk>

Test that the GICD_IIDR implementation revision correctly controls
guest-visible behaviour for GICv3:

  Revision 1: IGROUPR reads as all-ones (group 1), writes are ignored.
              GICR_CTLR.{IR,CES} not advertised.
  Revision 2: IGROUPR is guest-configurable (read/write).
              GICR_CTLR.{IR,CES} not advertised.
  Revision 3: IGROUPR is guest-configurable (read/write).
              GICR_CTLR.{IR,CES} advertised.

For each revision, the test sets the IIDR via KVM_DEV_ARM_VGIC_GRP_DIST_REGS
before initializing the vGIC, then runs a guest that verifies the
expected IGROUPR and GICR_CTLR behaviour.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
---
 tools/testing/selftests/kvm/Makefile.kvm      |   1 +
 .../selftests/kvm/arm64/vgic_group_iidr.c     | 118 ++++++++++++++++++
 2 files changed, 119 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/arm64/vgic_group_iidr.c

diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 9118a5a51b89..8cadfed4d79a 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -177,6 +177,7 @@ TEST_GEN_PROGS_arm64 += arm64/sea_to_user
 TEST_GEN_PROGS_arm64 += arm64/set_id_regs
 TEST_GEN_PROGS_arm64 += arm64/smccc_filter
 TEST_GEN_PROGS_arm64 += arm64/vcpu_width_config
+TEST_GEN_PROGS_arm64 += arm64/vgic_group_iidr
 TEST_GEN_PROGS_arm64 += arm64/vgic_init
 TEST_GEN_PROGS_arm64 += arm64/vgic_irq
 TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress
diff --git a/tools/testing/selftests/kvm/arm64/vgic_group_iidr.c b/tools/testing/selftests/kvm/arm64/vgic_group_iidr.c
new file mode 100644
index 000000000000..0073ccc19e92
--- /dev/null
+++ b/tools/testing/selftests/kvm/arm64/vgic_group_iidr.c
@@ -0,0 +1,118 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * vgic_group_iidr.c - Test IGROUPR behaviour across IIDR revisions
+ *
+ * Validate that the GICD_IIDR implementation revision controls
+ * IGROUPR semantics for GICv3:
+ *   Rev 1: IGROUPR reads as all-ones (group 1), writes ignored
+ *   Rev 2+: IGROUPR is guest-configurable (read/write)
+ */
+#include <linux/sizes.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+#include "gic.h"
+#include "gic_v3.h"
+#include "vgic.h"
+
+#define NR_IRQS		128
+#define SPI_IGROUPR	(GICD_IGROUPR + (32 / 32) * 4) /* intids 32-63 */
+
+static uint64_t shared_rev;
+
+static void guest_code(void)
+{
+	uint32_t val;
+
+	val = readl(GICD_BASE_GVA + SPI_IGROUPR);
+
+	if (shared_rev == 1) {
+		/* Rev 1: all group 1, guest writes must be ignored */
+		GUEST_ASSERT_EQ(val, 0xffffffff);
+		writel(0x0, GICD_BASE_GVA + SPI_IGROUPR);
+		val = readl(GICD_BASE_GVA + SPI_IGROUPR);
+		GUEST_ASSERT_EQ(val, 0xffffffff);
+		writel(0x55aa55aa, GICD_BASE_GVA + SPI_IGROUPR);
+		val = readl(GICD_BASE_GVA + SPI_IGROUPR);
+		GUEST_ASSERT_EQ(val, 0xffffffff);
+	} else {
+		/* Rev 2/3: guest-configurable */
+		writel(0xa5a5a5a5, GICD_BASE_GVA + SPI_IGROUPR);
+		val = readl(GICD_BASE_GVA + SPI_IGROUPR);
+		GUEST_ASSERT_EQ(val, 0xa5a5a5a5);
+		writel(0x0, GICD_BASE_GVA + SPI_IGROUPR);
+		val = readl(GICD_BASE_GVA + SPI_IGROUPR);
+		GUEST_ASSERT_EQ(val, 0x0);
+	}
+
+	/* Rev 3: GICR_CTLR advertises IR and CES. Rev 1/2: it does not. */
+	val = readl(GICR_BASE_GVA + GICR_CTLR);
+	if (shared_rev >= 3)
+		GUEST_ASSERT(val & (GICR_CTLR_IR | GICR_CTLR_CES));
+	else
+		GUEST_ASSERT(!(val & (GICR_CTLR_IR | GICR_CTLR_CES)));
+
+	GUEST_DONE();
+}
+
+static void run_test(int rev)
+{
+	struct kvm_vcpu *vcpus[1];
+	struct kvm_vm *vm;
+	struct ucall uc;
+	uint32_t iidr;
+	int gic_fd;
+
+	pr_info("Testing IIDR revision %d\n", rev);
+
+	test_disable_default_vgic();
+	vm = vm_create_with_vcpus(1, guest_code, vcpus);
+
+	gic_fd = __vgic_v3_setup(vm, 1, NR_IRQS);
+	TEST_ASSERT(gic_fd >= 0, "Failed to create vGICv3");
+
+	/* Set the requested IIDR revision before init. */
+	kvm_device_attr_get(gic_fd, KVM_DEV_ARM_VGIC_GRP_DIST_REGS,
+			    GICD_IIDR, &iidr);
+	iidr &= ~GICD_IIDR_REVISION_MASK;
+	iidr |= rev << GICD_IIDR_REVISION_SHIFT;
+	kvm_device_attr_set(gic_fd, KVM_DEV_ARM_VGIC_GRP_DIST_REGS,
+			    GICD_IIDR, &iidr);
+
+	__vgic_v3_init(gic_fd);
+
+	/* Verify the revision was applied. */
+	kvm_device_attr_get(gic_fd, KVM_DEV_ARM_VGIC_GRP_DIST_REGS,
+			    GICD_IIDR, &iidr);
+	TEST_ASSERT(((iidr & GICD_IIDR_REVISION_MASK) >> GICD_IIDR_REVISION_SHIFT) == rev,
+		    "IIDR revision readback: expected %d, got %d",
+		    rev, (iidr & GICD_IIDR_REVISION_MASK) >> GICD_IIDR_REVISION_SHIFT);
+
+	/* Tell the guest which revision we set. */
+	sync_global_to_guest(vm, shared_rev);
+	shared_rev = rev;
+	sync_global_to_guest(vm, shared_rev);
+
+	vcpu_run(vcpus[0]);
+	switch (get_ucall(vcpus[0], &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT(uc);
+		break;
+	case UCALL_DONE:
+		break;
+	default:
+		TEST_FAIL("Unexpected ucall %lu", uc.cmd);
+	}
+
+	close(gic_fd);
+	kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+	run_test(1);
+	run_test(2);
+	run_test(3);
+	return 0;
+}
-- 
2.51.0