From: Joao Martins <joao.m.mart...@oracle.com>
This is just meant to serve as an example on how we can implement
hypercalls. xen_version specifically since Qemu does all kind of
feature controllability. So handling that here seems appropriate.
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
target/i386/xen.c | 67 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 67 insertions(+)
diff --git a/target/i386/xen.c b/target/i386/xen.c
index d7e942289c..ee6f99523d 100644
--- a/target/i386/xen.c
+++ b/target/i386/xen.c
@@ -11,9 +11,14 @@
#include "qemu/osdep.h"
#include "kvm/kvm_i386.h"
+#include "exec/address-spaces.h"
#include "xen.h"
#include "trace.h"
+#include "standard-headers/xen/version.h"
+
+#define PAGE_OFFSET 0xffffffff80000000UL
+
/*
* Unhandled hypercalls error:
*
@@ -24,6 +29,28 @@
#define HCALL_ERR 0
#endif
+static void *gpa_to_hva(uint64_t gpa)
+{
+ MemoryRegionSection mrs;
+
+ mrs = memory_region_find(get_system_memory(), gpa, 1);
+ return !mrs.mr ? NULL : qemu_map_ram_ptr(mrs.mr->ram_block,
+ mrs.offset_within_region);
+}
+
+static void *gva_to_hva(CPUState *cs, uint64_t gva)
+{
+ struct kvm_translation t = { .linear_address = gva };
+ int err;
+
+ err = kvm_vcpu_ioctl(cs, KVM_TRANSLATE, &t);
+ if (err || !t.valid) {
+ return NULL;
+ }
+
+ return gpa_to_hva(t.physical_address);
+}
+
int kvm_xen_init(KVMState *s, uint32_t xen_version)
{
const int required_caps = KVM_XEN_HVM_CONFIG_HYPERCALL_MSR |
@@ -59,6 +86,43 @@ int kvm_xen_init(KVMState *s, uint32_t xen_version)
return 0;
}
+static int kvm_xen_hcall_xen_version(struct kvm_xen_exit *exit, X86CPU *cpu,
+ int cmd, uint64_t arg)
+{
+ int err = 0;
+
+ switch (cmd) {
+ case XENVER_get_features: {
+ struct xen_feature_info *fi;
+
+ fi = gva_to_hva(CPU(cpu), arg);
+ if (!fi) {
+ err = -EFAULT;
+ break;
+ }
+
+ if (fi->submap_idx != 0) {
+ err = -EINVAL;
+ break;
+ }
+
+ /*
+ * There's only HVM guests and we only expose what
+ * we intend to support. These are left in the open
+ * whether we should or not support them:
+ *
+ * XENFEAT_memory_op_vnode_supported
+ * XENFEAT_writable_page_tables
+ */
+ fi->submap = (1U << XENFEAT_auto_translated_physmap);
+ break;
+ }
+ }
+
+ exit->u.hcall.result = err;
+ return err ? HCALL_ERR : 0;
+}
+
static int __kvm_xen_handle_exit(X86CPU *cpu, struct kvm_xen_exit *exit)
{
uint16_t code = exit->u.hcall.input;
@@ -69,6 +133,9 @@ static int __kvm_xen_handle_exit(X86CPU *cpu, struct
kvm_xen_exit *exit)
}
switch (code) {
+ case __HYPERVISOR_xen_version:
+ return kvm_xen_hcall_xen_version(exit, cpu, exit->u.hcall.params[0],
+ exit->u.hcall.params[1]);
default:
exit->u.hcall.result = -ENOSYS;
return HCALL_ERR;
--
2.35.3
