From 1a82b664efbd3f447bf752f1e6b5abd33903c8aa Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Date: Fri, 5 Oct 2012 11:35:14 +0200
Subject: [PATCH] nova: determine number of CPUs

Issue #813
---
 base-nova/include/nova/syscall-generic.h | 16 ++++++++++++++++
 base-nova/src/core/include/platform.h    |  4 ++++
 base-nova/src/core/platform.cc           |  6 +++++-
 3 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/base-nova/include/nova/syscall-generic.h b/base-nova/include/nova/syscall-generic.h
index 07dc41333c..f5676eecbf 100644
--- a/base-nova/include/nova/syscall-generic.h
+++ b/base-nova/include/nova/syscall-generic.h
@@ -123,6 +123,22 @@ namespace Nova {
 
 		bool has_feature_vmx() const { return feature_flags & (1 << 1); }
 		bool has_feature_svm() const { return feature_flags & (1 << 2); }
+
+		unsigned cpu_max() const {
+			return (mem_desc_offset - cpu_desc_offset) / cpu_desc_size; }
+
+		unsigned cpus() const {
+			unsigned cpu_num = 0;
+			const char * cpu_desc =
+				reinterpret_cast<const char *>(this) + cpu_desc_offset;
+
+			for (unsigned i = 0; i < cpu_max(); i++) {
+				if ((*cpu_desc) & 0x1) cpu_num++;
+				cpu_desc += cpu_desc_size; 
+			}
+
+			return cpu_num;
+		}
 	} __attribute__((packed));
 
 
diff --git a/base-nova/src/core/include/platform.h b/base-nova/src/core/include/platform.h
index 77202cc18d..17c308b05d 100644
--- a/base-nova/src/core/include/platform.h
+++ b/base-nova/src/core/include/platform.h
@@ -42,6 +42,9 @@ namespace Genode {
 			const addr_t _vm_base;
 			size_t _vm_size;
 
+			/* available CPUs */
+			unsigned _cpus;
+
 			addr_t _map_page(addr_t const phys_page, addr_t const pages,
 			                 bool const extra_page);
 			void _unmap_page(addr_t const phys, addr_t const virt,
@@ -71,6 +74,7 @@ namespace Genode {
 
 			void wait_for_exit();
 			bool supports_unmap() { return true; }
+			unsigned num_cpus() const { return _cpus; }
 
 
 			/*******************
diff --git a/base-nova/src/core/platform.cc b/base-nova/src/core/platform.cc
index fa9257dbec..6fdd202f98 100644
--- a/base-nova/src/core/platform.cc
+++ b/base-nova/src/core/platform.cc
@@ -289,13 +289,16 @@ static void init_core_page_fault_handler()
 Platform::Platform() :
 	_io_mem_alloc(core_mem_alloc()), _io_port_alloc(core_mem_alloc()),
 	_irq_alloc(core_mem_alloc()),
-	_vm_base(0x1000), _vm_size(0)
+	_vm_base(0x1000), _vm_size(0), _cpus(1)
 {
 	Hip  *hip  = (Hip *)__initial_sp;
 	/* check for right API version */
 	if (hip->api_version != 6)
 		nova_die();
 
+	/* determine number of available CPUs */
+	_cpus = hip->cpus();
+
 	/* register UTCB of main thread */
 	__main_thread_utcb = (Utcb *)(__initial_sp - get_page_size());
 
@@ -338,6 +341,7 @@ Platform::Platform() :
 	if (verbose_boot_info) {
 		printf("Hypervisor %s VMX\n", hip->has_feature_vmx() ? "features" : "does not feature");
 		printf("Hypervisor %s SVM\n", hip->has_feature_svm() ? "features" : "does not feature");
+		printf("Hypervisor reports %u CPU%c\n", _cpus, _cpus > 1 ? 's' : ' ');
 	}
 
 	/* initialize core allocators */