[PATCH 6/6] kvmppc: kvm-userspace: device tree modification for magic page

[ehrhardt@linux.vnet.ibm.com]

From: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>

This patch to kvm-userspace connects the other host & guest patches in this
series. On guest initialization it checks the hosts capabilities for the
magicpage mechanism. If available the device tree passed to the guest gets the
"hypervisor" node added and in that node the feature flag and the requested
magic page size (read from the host kernel via an ioctl) is stored.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
---

[diffstat]
 libkvm/libkvm-powerpc.c |    6 ++++++
 libkvm/libkvm.h         |    6 ++++++
 qemu/hw/device_tree.c   |   10 ++++++++++
 qemu/hw/device_tree.h   |    1 +
 qemu/hw/ppc440_bamboo.c |   15 +++++++++++++++
 qemu/qemu-kvm-powerpc.c |    5 +++++
 qemu/qemu-kvm.h         |    1 +
 7 files changed, 44 insertions(+)

[diff]

diff --git a/libkvm/libkvm-powerpc.c b/libkvm/libkvm-powerpc.c
--- a/libkvm/libkvm-powerpc.c
+++ b/libkvm/libkvm-powerpc.c
@@ -19,6 +19,7 @@
 
 #include "libkvm.h"
 #include "kvm-powerpc.h"
+#include <sys/ioctl.h>
 #include <errno.h>
 #include <stdio.h>
 #include <inttypes.h>
@@ -105,6 +106,11 @@
 	return 0;
 }
 
+int kvm_get_magicpage_size(kvm_context_t kvm)
+{
+	return ioctl(kvm->fd, KVM_GET_PPCPV_MAGICPAGE_SIZE, 0);
+}
+
 int kvm_arch_run(struct kvm_run *run, kvm_context_t kvm, int vcpu)
 {
 	int ret = 0;
diff --git a/libkvm/libkvm.h b/libkvm/libkvm.h
--- a/libkvm/libkvm.h
+++ b/libkvm/libkvm.h
@@ -639,6 +639,10 @@
 
 #endif
 
+#ifdef KVM_CAP_PPCPV_MAGICPAGE
+int kvm_get_magicpage_size(kvm_context_t kvm);
+#endif
+
 int kvm_translate(kvm_context_t kvm, int vcpu, struct kvm_translation *tr);
 
 #endif
diff --git a/qemu/hw/device_tree.c b/qemu/hw/device_tree.c
--- a/qemu/hw/device_tree.c
+++ b/qemu/hw/device_tree.c
@@ -190,4 +190,14 @@
 		exit(1);
 	}
 }
+
+void dt_add_subnode(void *fdt, const char *name, char *node_path)
+{
+	int offset;
+	offset = get_offset_of_node(fdt, node_path);
+	if (fdt_add_subnode(fdt, offset, name) < 0) {
+		printf("Unable to create device tree node '%s'\n", name);
+		exit(1);
+	}
+}
 #endif
diff --git a/qemu/hw/device_tree.h b/qemu/hw/device_tree.h
--- a/qemu/hw/device_tree.h
+++ b/qemu/hw/device_tree.h
@@ -23,4 +23,5 @@
 		uint32_t *val_array, int size);
 void dt_string(void *fdt, char *node_path, char *property,
 		char *string);
+void dt_add_subnode(void *fdt, const char *name, char *node_path);
 #endif
diff --git a/qemu/hw/ppc440_bamboo.c b/qemu/hw/ppc440_bamboo.c
--- a/qemu/hw/ppc440_bamboo.c
+++ b/qemu/hw/ppc440_bamboo.c
@@ -51,6 +51,7 @@
 	uint32_t cpu_freq;
 	uint32_t timebase_freq;
 	uint32_t mem_reg_property[]={0, 0, ram_size};
+	int pv_magicpage_size;
 
 	printf("%s: START\n", __func__);
 
@@ -167,6 +168,23 @@
 	dt_cell(fdt, "/chosen", "linux,initrd-end",
 				(initrd_base + initrd_size));
 	dt_string(fdt, "/chosen", "bootargs", (char *)kernel_cmdline);
+
+	if (kvm_enabled()
+	    && kvm_qemu_check_extension(KVM_CAP_PPCPV_MAGICPAGE)) {
+		pv_magicpage_size = kvmppc_pv_get_magicpage_size();
+		if (pv_magicpage_size < 0) {
+			fprintf(stderr, "%s: error reading magic page size\n",
+				 __func__);
+			exit(1);
+		}
+		dt_add_subnode(fdt, "hypervisor", "/");
+		dt_cell(fdt, "/hypervisor", "feature,pv-magicpage", 1);
+		dt_cell(fdt, "/hypervisor", "data,pv-magicpage-size",
+			pv_magicpage_size);
+		printf("%s: added pvmem request to device tree (%d bytes)\n",
+			 __func__, pv_magicpage_size);
+	}
+
 #endif
 
 	if (kvm_enabled()) {
diff --git a/qemu/qemu-kvm-powerpc.c b/qemu/qemu-kvm-powerpc.c
--- a/qemu/qemu-kvm-powerpc.c
+++ b/qemu/qemu-kvm-powerpc.c
@@ -214,6 +214,11 @@
     return 0; /* XXX ignore failed DCR ops */
 }
 
+int kvmppc_pv_get_magicpage_size(void)
+{
+	return kvm_get_magicpage_size(kvm_context);
+}
+
 int mmukvm_get_physical_address(CPUState *env, mmu_ctx_t *ctx,
                                 target_ulong eaddr, int rw, int access_type)
 {
diff --git a/qemu/qemu-kvm.h b/qemu/qemu-kvm.h
--- a/qemu/qemu-kvm.h
+++ b/qemu/qemu-kvm.h
@@ -86,6 +86,7 @@
 #ifdef TARGET_PPC
 int handle_powerpc_dcr_read(int vcpu, uint32_t dcrn, uint32_t *data);
 int handle_powerpc_dcr_write(int vcpu,uint32_t dcrn, uint32_t data);
+int kvmppc_pv_get_magicpage_size();
 #endif
 
 #if !defined(SYS_signalfd)