Create memslot 0 at 0x100000000 (4GiB) to avoid it overlapping with
KVM's private memslot for the APIC-access page.
Without this change running large-enough selftests (high number of vCPUs
and/or guest memory) can result in KVM_CREATE_VCPU failing because the
APIC-access page memslot overlaps memslot 0 created by the selftest:
$ ./dirty_log_perf_test -v 256 -s anonymous_hugetlb_1gb -b 4G
Test iterations: 2
Testing guest mode: PA-bits:ANY, VA-bits:48, 4K pages
==== Test Assertion Failure ====
lib/kvm_util.c:1341: vcpu->fd >= 0
pid=53654 tid=53654 errno=17 - File exists
(stack trace empty)
KVM_CREATE_VCPU failed, rc: -1 errno: 17 (File exists)
Signed-off-by: David Matlack <dmatlack@xxxxxxxxxx>
---
tools/testing/selftests/kvm/include/x86_64/processor.h | 6 ++++++
tools/testing/selftests/kvm/lib/kvm_util.c | 7 ++++++-
2 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/include/x86_64/processor.h b/tools/testing/selftests/kvm/include/x86_64/processor.h
index 3bd03b088dda..ee33528007ee 100644
--- a/tools/testing/selftests/kvm/include/x86_64/processor.h
+++ b/tools/testing/selftests/kvm/include/x86_64/processor.h
@@ -20,6 +20,12 @@
#include "../kvm_util.h"
+/*
+ * Create memslot 0 at 4GiB to avoid overlapping with KVM's private memslot for
+ * the APIC-access page at 0xfee00000.
+ */
+#define KVM_UTIL_MEMSLOT0_GPA 0x100000000ULL
+
extern bool host_cpu_is_intel;
extern bool host_cpu_is_amd;
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index b2262b5fad9e..c8d7e66d308d 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -20,6 +20,10 @@
#define KVM_UTIL_MIN_PFN 2
+#ifndef KVM_UTIL_MEMSLOT0_GPA
+#define KVM_UTIL_MEMSLOT0_GPA 0ULL
+#endif
+
static int vcpu_mmap_sz(void);
int open_path_or_exit(const char *path, int flags)
@@ -418,7 +422,8 @@ struct kvm_vm *__vm_create(struct vm_shape shape, uint32_t nr_runnable_vcpus,
vm = ____vm_create(shape);
- vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, 0, 0, nr_pages, 0);
+ vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+ KVM_UTIL_MEMSLOT0_GPA, 0, nr_pages, 0);
for (i = 0; i < NR_MEM_REGIONS; i++)
vm->memslots[i] = 0;
base-commit: 0c64952fec3ea01cb5b09f00134200f3e7ab40d5
--
2.44.0.278.ge034bb2e1d-goog
