From: Joao Martins <joao.m.mart...@oracle.com>
Introduce support for emulating CPUID for Xen HVM guests. It doesn't make
sense to advertise the KVM leaves to a Xen guest, so do it unconditionally
when the xen-version machine property is set.
Signed-off-by: Joao Martins <joao.m.mart...@oracle.com>
[dwmw2: Obtain xen_version from machine property, make it automatic]
Signed-off-by: David Woodhouse <d...@amazon.co.uk>
---
target/i386/cpu.c | 1 +
target/i386/cpu.h | 2 ++
target/i386/kvm/kvm.c | 72 +++++++++++++++++++++++++++++++++++++++++--
target/i386/xen.h | 8 +++++
4 files changed, 80 insertions(+), 3 deletions(-)
diff --git a/target/i386/cpu.c b/target/i386/cpu.c
index 22b681ca37..50aa95f134 100644
--- a/target/i386/cpu.c
+++ b/target/i386/cpu.c
@@ -7069,6 +7069,7 @@ static Property x86_cpu_properties[] = {
* own cache information (see x86_cpu_load_def()).
*/
DEFINE_PROP_BOOL("legacy-cache", X86CPU, legacy_cache, true),
+ DEFINE_PROP_BOOL("xen-vapic", X86CPU, xen_vapic, false),
/*
* From "Requirements for Implementing the Microsoft
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index d4bc19577a..c6c57baed5 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1964,6 +1964,8 @@ struct ArchCPU {
int32_t thread_id;
int32_t hv_max_vps;
+
+ bool xen_vapic;
};
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 0a2069b117..0d3eddf9de 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -22,6 +22,7 @@
#include <linux/kvm.h>
#include "standard-headers/asm-x86/kvm_para.h"
+#include "standard-headers/xen/arch-x86/cpuid.h"
#include "cpu.h"
#include "host-cpu.h"
@@ -1752,14 +1753,13 @@ int kvm_arch_init_vcpu(CPUState *cs)
X86CPU *cpu = X86_CPU(cs);
CPUX86State *env = &cpu->env;
uint32_t limit, i, j, cpuid_i;
- uint32_t unused;
+ uint32_t unused, xen_version = 0;
struct kvm_cpuid_entry2 *c;
uint32_t signature[3];
int kvm_base = KVM_CPUID_SIGNATURE;
int max_nested_state_len;
int r;
Error *local_err = NULL;
-
memset(&cpuid_data, 0, sizeof(cpuid_data));
cpuid_i = 0;
@@ -1811,7 +1811,73 @@ int kvm_arch_init_vcpu(CPUState *cs)
has_msr_hv_hypercall = true;
}
- if (cpu->expose_kvm) {
+ xen_version = kvm_arch_xen_version(MACHINE(qdev_get_machine()));
+ if (xen_version) {
+#ifdef CONFIG_XEN_EMU
+ struct kvm_cpuid_entry2 *xen_max_leaf;
+
+ memcpy(signature, "XenVMMXenVMM", 12);
+
+ xen_max_leaf = c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_SIGNATURE;
+ c->eax = kvm_base + XEN_CPUID_TIME;
+ c->ebx = signature[0];
+ c->ecx = signature[1];
+ c->edx = signature[2];
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_VENDOR;
+ c->eax = xen_version;
+ c->ebx = 0;
+ c->ecx = 0;
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_HVM_MSR;
+ /* Number of hypercall-transfer pages */
+ c->eax = 1;
+ /* Hypercall MSR base address */
+ c->ebx = XEN_HYPERCALL_MSR;
+ c->ecx = 0;
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_TIME;
+ c->eax = ((!!tsc_is_stable_and_known(env) << 1) |
+ (!!(env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_RDTSCP) << 2));
+ /* default=0 (emulate if necessary) */
+ c->ebx = 0;
+ /* guest tsc frequency */
+ c->ecx = env->user_tsc_khz;
+ /* guest tsc incarnation (migration count) */
+ c->edx = 0;
+
+ c = &cpuid_data.entries[cpuid_i++];
+ c->function = kvm_base + XEN_CPUID_HVM;
+ xen_max_leaf->eax = kvm_base + XEN_CPUID_HVM;
+ if (xen_version >= XEN_VERSION(4,5)) {
+ c->function = kvm_base + XEN_CPUID_HVM;
+
+ if (cpu->xen_vapic) {
+ c->eax |= XEN_HVM_CPUID_APIC_ACCESS_VIRT;
+ c->eax |= XEN_HVM_CPUID_X2APIC_VIRT;
+ }
+
+ c->eax |= XEN_HVM_CPUID_IOMMU_MAPPINGS;
+
+ if (xen_version >= XEN_VERSION(4,6)) {
+ c->eax |= XEN_HVM_CPUID_VCPU_ID_PRESENT;
+ c->ebx = cs->cpu_index;
+ }
+ }
+
+ kvm_base += 0x100;
+#else /* CONFIG_XEN_EMU */
+ /* This should never happen as kvm_arch_init() would have died first.
*/
+ fprintf(stderr, "Cannot enable Xen CPUID without Xen support\n");
+ abort();
+#endif
+ } else if (cpu->expose_kvm) {
memcpy(signature, "KVMKVMKVM\0\0\0", 12);
c = &cpuid_data.entries[cpuid_i++];
c->function = KVM_CPUID_SIGNATURE | kvm_base;
diff --git a/target/i386/xen.h b/target/i386/xen.h
index 6c4f3b7822..ae880c47bc 100644
--- a/target/i386/xen.h
+++ b/target/i386/xen.h
@@ -14,6 +14,14 @@
#define XEN_HYPERCALL_MSR 0x40000000
+#define XEN_CPUID_SIGNATURE 0
+#define XEN_CPUID_VENDOR 1
+#define XEN_CPUID_HVM_MSR 2
+#define XEN_CPUID_TIME 3
+#define XEN_CPUID_HVM 4
+
+#define XEN_VERSION(maj, min) ((maj) << 16 | (min))
+
int kvm_xen_init(KVMState *s, uint32_t xen_version);
#endif /* QEMU_I386_XEN_H */
--
2.35.3
