i386: Compile CPUX86State xsave_buf only when support KVM or HVF

While at it, also rename var to indicate it is not used only in KVM.
Reviewed-by: NNikita Leshchenko <nikita.leshchenko@oracle.com>
Reviewed-by: NPatrick Colp <patrick.colp@oracle.com>
Signed-off-by: NLiran Alon <liran.alon@oracle.com>
Message-Id: <20180914003827.124570-2-liran.alon@oracle.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

target/i386/cpu.h

@@ -1327,7 +1327,9 @@ typedef struct CPUX86State {
     bool tsc_valid;
     int64_t tsc_khz;
     int64_t user_tsc_khz; /* for sanity check only */
-    void *kvm_xsave_buf;
+#if defined(CONFIG_KVM) || defined(CONFIG_HVF)
+    void *xsave_buf;
+#endif
 #if defined(CONFIG_HVF)
     HVFX86EmulatorState *hvf_emul;
 #endif

target/i386/hvf/README.md

@@ -2,6 +2,6 @@
 
 These sources (and ../hvf-all.c) are adapted from Veertu Inc's vdhh (Veertu Desktop Hosted Hypervisor) (last known location: https://github.com/veertuinc/vdhh) with some minor changes, the most significant of which were:
 
-1. Adapt to our current QEMU's `CPUState` structure and `address_space_rw` API; many struct members have been moved around (emulated x86 state, kvm_xsave_buf) due to historical differences + QEMU needing to handle more emulation targets.
+1. Adapt to our current QEMU's `CPUState` structure and `address_space_rw` API; many struct members have been moved around (emulated x86 state, xsave_buf) due to historical differences + QEMU needing to handle more emulation targets.
 2. Removal of `apic_page` and hyperv-related functionality.
 3. More relaxed use of `qemu_mutex_lock_iothread`.

target/i386/hvf/hvf.c

@@ -587,7 +587,7 @@ int hvf_init_vcpu(CPUState *cpu)
     hvf_reset_vcpu(cpu);
 
     x86cpu = X86_CPU(cpu);
-    x86cpu->env.kvm_xsave_buf = qemu_memalign(4096, 4096);
+    x86cpu->env.xsave_buf = qemu_memalign(4096, 4096);
 
     hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_STAR, 1);
     hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_LSTAR, 1);

target/i386/hvf/x86hvf.c

@@ -75,7 +75,7 @@ void hvf_put_xsave(CPUState *cpu_state)
 
     struct X86XSaveArea *xsave;
 
-    xsave = X86_CPU(cpu_state)->env.kvm_xsave_buf;
+    xsave = X86_CPU(cpu_state)->env.xsave_buf;
 
     x86_cpu_xsave_all_areas(X86_CPU(cpu_state), xsave);
 
@@ -163,7 +163,7 @@ void hvf_get_xsave(CPUState *cpu_state)
 {
     struct X86XSaveArea *xsave;
 
-    xsave = X86_CPU(cpu_state)->env.kvm_xsave_buf;
+    xsave = X86_CPU(cpu_state)->env.xsave_buf;
 
     if (hv_vcpu_read_fpstate(cpu_state->hvf_fd, (void*)xsave, 4096)) {
         abort();

target/i386/kvm.c

@@ -1189,7 +1189,7 @@ int kvm_arch_init_vcpu(CPUState *cs)
     }
 
     if (has_xsave) {
-        env->kvm_xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
+        env->xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
     }
     cpu->kvm_msr_buf = g_malloc0(MSR_BUF_SIZE);
 
@@ -1639,7 +1639,7 @@ ASSERT_OFFSET(XSAVE_PKRU, pkru_state);
 static int kvm_put_xsave(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;
-    X86XSaveArea *xsave = env->kvm_xsave_buf;
+    X86XSaveArea *xsave = env->xsave_buf;
 
     if (!has_xsave) {
         return kvm_put_fpu(cpu);
@@ -2081,7 +2081,7 @@ static int kvm_get_fpu(X86CPU *cpu)
 static int kvm_get_xsave(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;
-    X86XSaveArea *xsave = env->kvm_xsave_buf;
+    X86XSaveArea *xsave = env->xsave_buf;
     int ret;
 
     if (!has_xsave) {