target/i386: Pass buffer and length to XSAVE helper

In preparation for removing assumptions about XSAVE area offsets, pass
a buffer pointer and buffer length to the XSAVE helper functions.

Signed-off-by: David Edmondson <david.edmondson@oracle.com>
Message-Id: <20210705104632.2902400-5-david.edmondson@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

5 files changed, 29 insertions, 28 deletions

diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 92f9ca2..ada2941 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1667,6 +1667,7 @@ typedef struct CPUX86State {
     uint64_t apic_bus_freq;
 #if defined(CONFIG_KVM) || defined(CONFIG_HVF)
     void *xsave_buf;
+    uint32_t xsave_buf_len;
 #endif
 #if defined(CONFIG_KVM)
     struct kvm_nested_state *nested_state;
@@ -2227,8 +2228,8 @@ void x86_cpu_dump_local_apic_state(CPUState *cs, int flags);
 /* cpu.c */
 bool cpu_is_bsp(X86CPU *cpu);
 
-void x86_cpu_xrstor_all_areas(X86CPU *cpu, const X86XSaveArea *buf);
-void x86_cpu_xsave_all_areas(X86CPU *cpu, X86XSaveArea *buf);
+void x86_cpu_xrstor_all_areas(X86CPU *cpu, const void *buf, uint32_t buflen);
+void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen);
 void x86_update_hflags(CPUX86State* env);
 
 static inline bool hyperv_feat_enabled(X86CPU *cpu, int feat)
diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c
index 346dbcc..e62e8df 100644
--- a/target/i386/hvf/hvf.c
+++ b/target/i386/hvf/hvf.c
@@ -267,7 +267,8 @@ int hvf_arch_init_vcpu(CPUState *cpu)
     wvmcs(cpu->hvf->fd, VMCS_TPR_THRESHOLD, 0);
 
     x86cpu = X86_CPU(cpu);
-    x86cpu->env.xsave_buf = qemu_memalign(4096, 4096);
+    x86cpu->env.xsave_buf_len = 4096;
+    x86cpu->env.xsave_buf = qemu_memalign(4096, x86cpu->env.xsave_buf_len);
 
     hv_vcpu_enable_native_msr(cpu->hvf->fd, MSR_STAR, 1);
     hv_vcpu_enable_native_msr(cpu->hvf->fd, MSR_LSTAR, 1);
diff --git a/target/i386/hvf/x86hvf.c b/target/i386/hvf/x86hvf.c
index 2ced2c2..05ec1bd 100644
--- a/target/i386/hvf/x86hvf.c
+++ b/target/i386/hvf/x86hvf.c
@@ -73,14 +73,12 @@ void hvf_get_segment(SegmentCache *qseg, struct vmx_segment *vmx_seg)
 
 void hvf_put_xsave(CPUState *cpu_state)
 {
+    void *xsave = X86_CPU(cpu_state)->env.xsave_buf;
+    uint32_t xsave_len = X86_CPU(cpu_state)->env.xsave_buf_len;
 
-    struct X86XSaveArea *xsave;
+    x86_cpu_xsave_all_areas(X86_CPU(cpu_state), xsave, xsave_len);
 
-    xsave = X86_CPU(cpu_state)->env.xsave_buf;
-
-    x86_cpu_xsave_all_areas(X86_CPU(cpu_state), xsave);
-
-    if (hv_vcpu_write_fpstate(cpu_state->hvf->fd, (void*)xsave, 4096)) {
+    if (hv_vcpu_write_fpstate(cpu_state->hvf->fd, xsave, xsave_len)) {
         abort();
     }
 }
@@ -158,15 +156,14 @@ void hvf_put_msrs(CPUState *cpu_state)
 
 void hvf_get_xsave(CPUState *cpu_state)
 {
-    struct X86XSaveArea *xsave;
-
-    xsave = X86_CPU(cpu_state)->env.xsave_buf;
+    void *xsave = X86_CPU(cpu_state)->env.xsave_buf;
+    uint32_t xsave_len = X86_CPU(cpu_state)->env.xsave_buf_len;
 
-    if (hv_vcpu_read_fpstate(cpu_state->hvf->fd, (void*)xsave, 4096)) {
+    if (hv_vcpu_read_fpstate(cpu_state->hvf->fd, xsave, xsave_len)) {
         abort();
     }
 
-    x86_cpu_xrstor_all_areas(X86_CPU(cpu_state), xsave);
+    x86_cpu_xrstor_all_areas(X86_CPU(cpu_state), xsave, xsave_len);
 }
 
 void hvf_get_segments(CPUState *cpu_state)
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 3ab1d71..41b0764 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1888,8 +1888,9 @@ int kvm_arch_init_vcpu(CPUState *cs)
     }
 
     if (has_xsave) {
-        env->xsave_buf = qemu_memalign(4096, sizeof(struct kvm_xsave));
-        memset(env->xsave_buf, 0, sizeof(struct kvm_xsave));
+        env->xsave_buf_len = sizeof(struct kvm_xsave);
+        env->xsave_buf = qemu_memalign(4096, env->xsave_buf_len);
+        memset(env->xsave_buf, 0, env->xsave_buf_len);
     }
 
     max_nested_state_len = kvm_max_nested_state_length();
@@ -2469,12 +2470,12 @@ static int kvm_put_fpu(X86CPU *cpu)
 static int kvm_put_xsave(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;
-    X86XSaveArea *xsave = env->xsave_buf;
+    void *xsave = env->xsave_buf;
 
     if (!has_xsave) {
         return kvm_put_fpu(cpu);
     }
-    x86_cpu_xsave_all_areas(cpu, xsave);
+    x86_cpu_xsave_all_areas(cpu, xsave, env->xsave_buf_len);
 
     return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_XSAVE, xsave);
 }
@@ -3119,7 +3120,7 @@ static int kvm_get_fpu(X86CPU *cpu)
 static int kvm_get_xsave(X86CPU *cpu)
 {
     CPUX86State *env = &cpu->env;
-    X86XSaveArea *xsave = env->xsave_buf;
+    void *xsave = env->xsave_buf;
     int ret;
 
     if (!has_xsave) {
@@ -3130,7 +3131,7 @@ static int kvm_get_xsave(X86CPU *cpu)
     if (ret < 0) {
         return ret;
     }
-    x86_cpu_xrstor_all_areas(cpu, xsave);
+    x86_cpu_xrstor_all_areas(cpu, xsave, env->xsave_buf_len);
 
     return 0;
 }
diff --git a/target/i386/xsave_helper.c b/target/i386/xsave_helper.c
index 818115e..b16c6ac 100644
--- a/target/i386/xsave_helper.c
+++ b/target/i386/xsave_helper.c
@@ -6,14 +6,16 @@
 
 #include "cpu.h"
 
-void x86_cpu_xsave_all_areas(X86CPU *cpu, X86XSaveArea *buf)
+void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen)
 {
     CPUX86State *env = &cpu->env;
     X86XSaveArea *xsave = buf;
-
     uint16_t cwd, swd, twd;
     int i;
-    memset(xsave, 0, sizeof(X86XSaveArea));
+
+    assert(buflen >= sizeof(*xsave));
+
+    memset(xsave, 0, buflen);
     twd = 0;
     swd = env->fpus & ~(7 << 11);
     swd |= (env->fpstt & 7) << 11;
@@ -56,17 +58,17 @@ void x86_cpu_xsave_all_areas(X86CPU *cpu, X86XSaveArea *buf)
             16 * sizeof env->xmm_regs[16]);
     memcpy(&xsave->pkru_state, &env->pkru, sizeof env->pkru);
 #endif
-
 }
 
-void x86_cpu_xrstor_all_areas(X86CPU *cpu, const X86XSaveArea *buf)
+void x86_cpu_xrstor_all_areas(X86CPU *cpu, const void *buf, uint32_t buflen)
 {
-
     CPUX86State *env = &cpu->env;
     const X86XSaveArea *xsave = buf;
-
     int i;
     uint16_t cwd, swd, twd;
+
+    assert(buflen >= sizeof(*xsave));
+
     cwd = xsave->legacy.fcw;
     swd = xsave->legacy.fsw;
     twd = xsave->legacy.ftw;
@@ -108,5 +110,4 @@ void x86_cpu_xrstor_all_areas(X86CPU *cpu, const X86XSaveArea *buf)
            16 * sizeof env->xmm_regs[16]);
     memcpy(&env->pkru, &xsave->pkru_state, sizeof env->pkru);
 #endif
-
 }