From: Joao Martins <joao.m.mart...@oracle.com>
Specifically XENMEM_add_to_physmap with space XENMAPSPACE_shared_info to
allow the guest to set its shared_info page.
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
[dwmw2: Use the xen_overlay device, add compat support]
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
Reviewed-by: Paul Durrant <p...@xen.org>
---
target/i386/kvm/trace-events | 1 +
target/i386/kvm/xen-compat.h | 27 ++++++++
target/i386/kvm/xen-emu.c | 116 ++++++++++++++++++++++++++++++++++-
3 files changed, 143 insertions(+), 1 deletion(-)
create mode 100644 target/i386/kvm/xen-compat.h
diff --git a/target/i386/kvm/trace-events b/target/i386/kvm/trace-events
index bb732e1da8..8e9f269f56 100644
--- a/target/i386/kvm/trace-events
+++ b/target/i386/kvm/trace-events
@@ -9,3 +9,4 @@ kvm_x86_update_msi_routes(int num) "Updated %d MSI routes"
# xen-emu.c
kvm_xen_hypercall(int cpu, uint8_t cpl, uint64_t input, uint64_t a0, uint64_t
a1, uint64_t a2, uint64_t ret) "xen_hypercall: cpu %d cpl %d input %" PRIu64 "
a0 0x%" PRIx64 " a1 0x%" PRIx64 " a2 0x%" PRIx64" ret 0x%" PRIx64
kvm_xen_soft_reset(void) ""
+kvm_xen_set_shared_info(uint64_t gfn) "shared info at gfn 0x%" PRIx64
diff --git a/target/i386/kvm/xen-compat.h b/target/i386/kvm/xen-compat.h
new file mode 100644
index 0000000000..2d852e2a28
--- /dev/null
+++ b/target/i386/kvm/xen-compat.h
@@ -0,0 +1,27 @@
+/*
+ * Xen HVM emulation support in KVM
+ *
+ * Copyright © 2022 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ *
+ */
+
+#ifndef QEMU_I386_KVM_XEN_COMPAT_H
+#define QEMU_I386_KVM_XEN_COMPAT_H
+
+#include "hw/xen/interface/memory.h"
+
+typedef uint32_t compat_pfn_t;
+typedef uint32_t compat_ulong_t;
+
+struct compat_xen_add_to_physmap {
+ domid_t domid;
+ uint16_t size;
+ unsigned int space;
+ compat_ulong_t idx;
+ compat_pfn_t gpfn;
+};
+
+#endif /* QEMU_I386_XEN_COMPAT_H */
diff --git a/target/i386/kvm/xen-emu.c b/target/i386/kvm/xen-emu.c
index be6d85f2cb..5d79827128 100644
--- a/target/i386/kvm/xen-emu.c
+++ b/target/i386/kvm/xen-emu.c
@@ -12,6 +12,7 @@
#include "qemu/osdep.h"
#include "qemu/log.h"
#include "qemu/main-loop.h"
+#include "hw/xen/xen.h"
#include "sysemu/kvm_int.h"
#include "sysemu/kvm_xen.h"
#include "kvm/kvm_i386.h"
@@ -24,6 +25,15 @@
#include "hw/xen/interface/version.h"
#include "hw/xen/interface/sched.h"
+#include "hw/xen/interface/memory.h"
+
+#include "xen-compat.h"
+
+#ifdef TARGET_X86_64
+#define hypercall_compat32(longmode) (!(longmode))
+#else
+#define hypercall_compat32(longmode) (false)
+#endif
static int kvm_gva_rw(CPUState *cs, uint64_t gva, void *_buf, size_t sz,
bool is_write)
@@ -175,13 +185,114 @@ static bool kvm_xen_hcall_xen_version(struct
kvm_xen_exit *exit, X86CPU *cpu,
return true;
}
+static int xen_set_shared_info(uint64_t gfn)
+{
+ uint64_t gpa = gfn << TARGET_PAGE_BITS;
+ int err;
+
+ QEMU_IOTHREAD_LOCK_GUARD();
+
+ /*
+ * The xen_overlay device tells KVM about it too, since it had to
+ * do that on migration load anyway (unless we're going to jump
+ * through lots of hoops to maintain the fiction that this isn't
+ * KVM-specific.
+ */
+ err = xen_overlay_map_shinfo_page(gpa);
+ if (err) {
+ return err;
+ }
+
+ trace_kvm_xen_set_shared_info(gfn);
+
+ return err;
+}
+
+static int add_to_physmap_one(uint32_t space, uint64_t idx, uint64_t gfn)
+{
+ switch (space) {
+ case XENMAPSPACE_shared_info:
+ if (idx > 0) {
+ return -EINVAL;
+ }
+ return xen_set_shared_info(gfn);
+
+ case XENMAPSPACE_grant_table:
+ case XENMAPSPACE_gmfn:
+ case XENMAPSPACE_gmfn_range:
+ return -ENOTSUP;
+
+ case XENMAPSPACE_gmfn_foreign:
+ case XENMAPSPACE_dev_mmio:
+ return -EPERM;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int do_add_to_physmap(struct kvm_xen_exit *exit, X86CPU *cpu,
+ uint64_t arg)
+{
+ struct xen_add_to_physmap xatp;
+ CPUState *cs = CPU(cpu);
+
+ if (hypercall_compat32(exit->u.hcall.longmode)) {
+ struct compat_xen_add_to_physmap xatp32;
+
+ qemu_build_assert(sizeof(struct compat_xen_add_to_physmap) == 16);
+ if (kvm_copy_from_gva(cs, arg, &xatp32, sizeof(xatp32))) {
+ return -EFAULT;
+ }
+ xatp.domid = xatp32.domid;
+ xatp.size = xatp32.size;
+ xatp.space = xatp32.space;
+ xatp.idx = xatp32.idx;
+ xatp.gpfn = xatp32.gpfn;
+ } else {
+ if (kvm_copy_from_gva(cs, arg, &xatp, sizeof(xatp))) {
+ return -EFAULT;
+ }
+ }
+
+ if (xatp.domid != DOMID_SELF && xatp.domid != xen_domid) {
+ return -ESRCH;
+ }
+
+ return add_to_physmap_one(xatp.space, xatp.idx, xatp.gpfn);
+}
+
+static bool kvm_xen_hcall_memory_op(struct kvm_xen_exit *exit, X86CPU *cpu,
+ int cmd, uint64_t arg)
+{
+ int err;
+
+ switch (cmd) {
+ case XENMEM_add_to_physmap:
+ err = do_add_to_physmap(exit, cpu, arg);
+ break;
+
+ default:
+ return false;
+ }
+
+ exit->u.hcall.result = err;
+ return true;
+}
+
int kvm_xen_soft_reset(void)
{
+ int err;
+
assert(qemu_mutex_iothread_locked());
trace_kvm_xen_soft_reset();
- /* Nothing to reset... yet. */
+ err = xen_overlay_map_shinfo_page(INVALID_GFN);
+ if (err) {
+ return err;
+ }
+
return 0;
}
@@ -270,6 +381,9 @@ static bool do_kvm_xen_handle_exit(X86CPU *cpu, struct
kvm_xen_exit *exit)
case __HYPERVISOR_sched_op:
return kvm_xen_hcall_sched_op(exit, cpu, exit->u.hcall.params[0],
exit->u.hcall.params[1]);
+ case __HYPERVISOR_memory_op:
+ return kvm_xen_hcall_memory_op(exit, cpu, exit->u.hcall.params[0],
+ exit->u.hcall.params[1]);
case __HYPERVISOR_xen_version:
return kvm_xen_hcall_xen_version(exit, cpu, exit->u.hcall.params[0],
exit->u.hcall.params[1]);
--
2.39.0
