[PATCH v2 3/6] KVM: selftests: Add additional pages to the guest to accommodate ucall

From: Aaron Lewis <aaronlewis@google.com>
To: kvm@vger.kernel.org
Cc: pbonzini@redhat.com, jmattson@google.com, seanjc@google.com,
	Aaron Lewis <aaronlewis@google.com>
Subject: [PATCH v2 3/6] KVM: selftests: Add additional pages to the guest to accommodate ucall
Date: Mon, 24 Apr 2023 22:58:51 +0000	[thread overview]
Message-ID: <20230424225854.4023978-4-aaronlewis@google.com> (raw)
In-Reply-To: <20230424225854.4023978-1-aaronlewis@google.com>

Add additional pages to the guest to account for the number of pages
the ucall framework uses.

This is done in preparation for adding string formatting options to
the guest through ucall helpers.

Signed-off-by: Aaron Lewis <aaronlewis@google.com>
---
 tools/testing/selftests/kvm/include/ucall_common.h | 1 +
 tools/testing/selftests/kvm/lib/kvm_util.c         | 4 ++++
 tools/testing/selftests/kvm/lib/ucall_common.c     | 5 +++++
 3 files changed, 10 insertions(+)

diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h
index 1a6aaef5ccae..bcbb362aa77f 100644
--- a/tools/testing/selftests/kvm/include/ucall_common.h
+++ b/tools/testing/selftests/kvm/include/ucall_common.h
@@ -34,6 +34,7 @@ void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu);
 void ucall(uint64_t cmd, int nargs, ...);
 uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc);
 void ucall_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa);
+int ucall_nr_pages_required(uint64_t page_size);
 
 /*
  * Perform userspace call without any associated data.  This bare call avoids
diff --git a/tools/testing/selftests/kvm/lib/kvm_util.c b/tools/testing/selftests/kvm/lib/kvm_util.c
index 298c4372fb1a..80b3df2a79e6 100644
--- a/tools/testing/selftests/kvm/lib/kvm_util.c
+++ b/tools/testing/selftests/kvm/lib/kvm_util.c
@@ -312,6 +312,7 @@ static uint64_t vm_nr_pages_required(enum vm_guest_mode mode,
 				     uint32_t nr_runnable_vcpus,
 				     uint64_t extra_mem_pages)
 {
+	uint64_t page_size = vm_guest_mode_params[mode].page_size;
 	uint64_t nr_pages;
 
 	TEST_ASSERT(nr_runnable_vcpus,
@@ -340,6 +341,9 @@ static uint64_t vm_nr_pages_required(enum vm_guest_mode mode,
 	 */
 	nr_pages += (nr_pages + extra_mem_pages) / PTES_PER_MIN_PAGE * 2;
 
+	/* Account for the number of pages needed by ucall. */
+	nr_pages += ucall_nr_pages_required(page_size);
+
 	return vm_adjust_num_guest_pages(mode, nr_pages);
 }
 
diff --git a/tools/testing/selftests/kvm/lib/ucall_common.c b/tools/testing/selftests/kvm/lib/ucall_common.c
index 2f0e2ea941cc..77ada362273d 100644
--- a/tools/testing/selftests/kvm/lib/ucall_common.c
+++ b/tools/testing/selftests/kvm/lib/ucall_common.c
@@ -11,6 +11,11 @@ struct ucall_header {
 	struct ucall ucalls[KVM_MAX_VCPUS];
 };
 
+int ucall_nr_pages_required(uint64_t page_size)
+{
+	return align_up(sizeof(struct ucall_header), page_size) / page_size;
+}
+
 /*
  * ucall_pool holds per-VM values (global data is duplicated by each VM), it
  * must not be accessed from host code.
-- 
2.40.0.634.g4ca3ef3211-goog

