[RFC PATCH 6/7] x86: Use new XSAVE ioctls handling

[Yang Zhong]

From: Jing Liu <jing2.liu@intel.com>

Extended feature has large state while current
kvm_xsave only allows 4KB. Use new XSAVE ioctls
if the xstate size is large than kvm_xsave.

Signed-off-by: Jing Liu <jing2.liu@intel.com>
Signed-off-by: Zeng Guang <guang.zeng@intel.com>
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Signed-off-by: Yang Zhong <yang.zhong@intel.com>
---
 linux-headers/asm-x86/kvm.h | 14 ++++++++++++++
 linux-headers/linux/kvm.h   |  2 ++
 target/i386/cpu.h           |  5 +++++
 target/i386/kvm/kvm.c       | 16 ++++++++++++++--
 target/i386/xsave_helper.c  | 35 +++++++++++++++++++++++++++++++++++
 5 files changed, 70 insertions(+), 2 deletions(-)

diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h
index 5a776a08f7..32f2a921e8 100644
--- a/linux-headers/asm-x86/kvm.h
+++ b/linux-headers/asm-x86/kvm.h
@@ -376,6 +376,20 @@ struct kvm_debugregs {
 /* for KVM_CAP_XSAVE */
 struct kvm_xsave {
        __u32 region[1024];
+       /*
+        * KVM_GET_XSAVE2 and KVM_SET_XSAVE write and read as many bytes
+        * as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2)
+        * respectively, when invoked on the vm file descriptor.
+        *
+        * The size value returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2)
+        * will always be at least 4096. Currently, it is only greater
+        * than 4096 if a dynamic feature has been enabled with
+        * ``arch_prctl()``, but this may change in the future.
+        *
+        * The offsets of the state save areas in struct kvm_xsave follow
+        * the contents of CPUID leaf 0xD on the host.
+        */
+       __u32 extra[0];
 };
 
 #define KVM_MAX_XCRS   16
diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h
index 02c5e7b7bb..97d5b6d81d 100644
--- a/linux-headers/linux/kvm.h
+++ b/linux-headers/linux/kvm.h
@@ -1130,6 +1130,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_BINARY_STATS_FD 203
 #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204
 #define KVM_CAP_ARM_MTE 205
+#define KVM_CAP_XSAVE2  207
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1550,6 +1551,7 @@ struct kvm_s390_ucas_mapping {
 /* Available with KVM_CAP_XSAVE */
 #define KVM_GET_XSAVE            _IOR(KVMIO,  0xa4, struct kvm_xsave)
 #define KVM_SET_XSAVE            _IOW(KVMIO,  0xa5, struct kvm_xsave)
+#define KVM_GET_XSAVE2           _IOR(KVMIO,  0xcf, struct kvm_xsave)
 /* Available with KVM_CAP_XCRS */
 #define KVM_GET_XCRS             _IOR(KVMIO,  0xa6, struct kvm_xcrs)
 #define KVM_SET_XCRS             _IOW(KVMIO,  0xa7, struct kvm_xcrs)
diff --git a/target/i386/cpu.h b/target/i386/cpu.h
index 245e8b5a1a..6153c4ab1a 100644
--- a/target/i386/cpu.h
+++ b/target/i386/cpu.h
@@ -1519,6 +1519,11 @@ typedef struct CPUX86State {
     YMMReg zmmh_regs[CPU_NB_REGS];
     ZMMReg hi16_zmm_regs[CPU_NB_REGS];
 
+#ifdef TARGET_X86_64
+    uint8_t xtilecfg[64];
+    uint8_t xtiledata[8192];
+#endif
+
     /* sysenter registers */
     uint32_t sysenter_cs;
     target_ulong sysenter_esp;
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 3fb3ddbe2b..97520e9dff 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -1983,7 +1983,12 @@ int kvm_arch_init_vcpu(CPUState *cs)
     }
 
     if (has_xsave) {
-        env->xsave_buf_len = sizeof(struct kvm_xsave);
+        uint32_t size = kvm_vm_check_extension(cs->kvm_state, KVM_CAP_XSAVE2);
+        if (!size) {
+            size = sizeof(struct kvm_xsave);
+        }
+
+        env->xsave_buf_len = QEMU_ALIGN_UP(size, 4096);
         env->xsave_buf = qemu_memalign(4096, env->xsave_buf_len);
         memset(env->xsave_buf, 0, env->xsave_buf_len);
 
@@ -2580,6 +2585,7 @@ static int kvm_put_xsave(X86CPU *cpu)
     if (!has_xsave) {
         return kvm_put_fpu(cpu);
     }
+
     x86_cpu_xsave_all_areas(cpu, xsave, env->xsave_buf_len);
 
     return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_XSAVE, xsave);
@@ -3247,10 +3253,16 @@ static int kvm_get_xsave(X86CPU *cpu)
         return kvm_get_fpu(cpu);
     }
 
-    ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE, xsave);
+    if (env->xsave_buf_len <= sizeof(struct kvm_xsave)) {
+        ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE, xsave);
+    } else {
+        ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE2, xsave);
+    }
+
     if (ret < 0) {
         return ret;
     }
+
     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 ac61a96344..090424e820 100644
--- a/target/i386/xsave_helper.c
+++ b/target/i386/xsave_helper.c
@@ -5,6 +5,7 @@
 #include "qemu/osdep.h"
 
 #include "cpu.h"
+#include <asm/kvm.h>
 
 void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen)
 {
@@ -126,6 +127,23 @@ void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, 
uint32_t buflen)
 
         memcpy(pkru, &env->pkru, sizeof(env->pkru));
     }
+
+    e = &x86_ext_save_areas[XSTATE_XTILE_CFG_BIT];
+    if (e->size && e->offset) {
+        XSaveXTILE_CFG *tilecfg = buf + e->offset;
+
+        memcpy(tilecfg, &env->xtilecfg, sizeof(env->xtilecfg));
+    }
+
+    if (buflen > sizeof(struct kvm_xsave)) {
+        e = &x86_ext_save_areas[XSTATE_XTILE_DATA_BIT];
+
+        if (e->size && e->offset) {
+            XSaveXTILE_DATA *tiledata = buf + e->offset;
+
+            memcpy(tiledata, &env->xtiledata, sizeof(env->xtiledata));
+        }
+    }
 #endif
 }
 
@@ -247,5 +265,22 @@ void x86_cpu_xrstor_all_areas(X86CPU *cpu, const void 
*buf, uint32_t buflen)
         pkru = buf + e->offset;
         memcpy(&env->pkru, pkru, sizeof(env->pkru));
     }
+
+    e = &x86_ext_save_areas[XSTATE_XTILE_CFG_BIT];
+    if (e->size && e->offset) {
+        const XSaveXTILE_CFG *tilecfg = buf + e->offset;
+
+        memcpy(&env->xtilecfg, tilecfg, sizeof(env->xtilecfg));
+    }
+
+    if (buflen > sizeof(struct kvm_xsave)) {
+        e = &x86_ext_save_areas[XSTATE_XTILE_DATA_BIT];
+
+        if (e->size && e->offset) {
+            const XSaveXTILE_DATA *tiledata = buf + e->offset;
+
+            memcpy(&env->xtiledata, tiledata, sizeof(env->xtiledata));
+        }
+    }
 #endif
 }