[PATCH v7 5/8] KVM: selftests: Add helper for checking if running on powerpc pseries LPAR

["Ritesh Harjani (IBM)" <ritesh.list@gmail.com>]

PowerPC's PAPR L0 does not guarantee H_GUEST_CREATE/H_GUEST_CREATE_VCPU
hcalls to create upto MAX_VCPUS or hundreds of VMs, this is due to
limited resouces at L0 for guest management space. This helper allows us
to skip such tests which creates a lot of VMs/VCPUs, when we are running
nested.

Note that there is no easy way to differentiate between running nested
on PowerNV v/s kvm-on-powervm case. So we use a common helper to detect
any nested case.

The helper is added to the common kvm_util header file to avoid
sprinkling multiple #ifdef __powerpc64__ everywhere.

Suggested-by: Sean Christopherson <seanjc@google.com>
Tested-by: Anushree Mathur <anushree.mathur@linux.ibm.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
---
 tools/testing/selftests/kvm/include/kvm_util.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 9df16c8dc82a..258ae5879a5e 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -14,6 +14,7 @@
 #include <linux/kvm.h>
 #include "linux/rbtree.h"
 #include <linux/types.h>
+#include <unistd.h>
 
 #include <asm/atomic.h>
 #include <asm/kvm.h>
@@ -1063,6 +1064,22 @@ const char *exit_reason_str(unsigned int exit_reason);
 
 bool kvm_arch_needs_naturally_aligned_page_tables(void);
 
+/*
+ * True on powerpc when this host is a pseries LPAR (nested case).
+ * PowerPC's PAPR L0 does not guarantee H_GUEST_CREATE / H_GUEST_CREATE_VCPU up
+ * to MAX_VCPUS or creating hundreds of VMs - due to limited resouces at L0 for
+ * guest management space. This helper allows us to skip such tests when we are
+ * running nested.
+ */
+static inline bool kvm_is_ppc_pseries_lpar(void)
+{
+#ifdef __powerpc64__
+	return !access("/proc/device-tree/rtas/ibm,hypertas-functions", F_OK);
+#else
+	return false;
+#endif
+}
+
 gpa_t ____vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages, gpa_t min_gpa,
 			     u32 memslot, bool protected, bool naturally_aligned);
 gpa_t __vm_phy_pages_alloc(struct kvm_vm *vm, size_t nr_pages,
-- 
2.39.5