From ae580956fc0ed8feb794b6392df59ff5de673565 Mon Sep 17 00:00:00 2001

From: David Edmondson <david.edmondson@oracle.com>

Date: Mon, 5 Jul 2021 11:46:31 +0100

Subject: [PATCH 7/7] target/i386: Populate x86_ext_save_areas offsets using

 cpuid where possible

RH-Author: Dr. David Alan Gilbert <dgilbert@redhat.com>

RH-MergeRequest: 113: non-av 8.5z: Fix XSAVE on newer CPUs

RH-Commit: [7/7] 145fc1dd5232673e2070423a027cad38fa4c4890

RH-Bugzilla: 2065239

RH-Acked-by: Jon Maloy <jmaloy@redhat.com>

RH-Acked-by: Paolo Bonzini <pbonzini@redhat.com>

RH-Acked-by: Bandan Das <None>

Rather than relying on the X86XSaveArea structure definition,

determine the offset of XSAVE state areas using CPUID leaf 0xd where

possible (KVM and HVF).

Signed-off-by: David Edmondson <david.edmondson@oracle.com>

Message-Id: <20210705104632.2902400-8-david.edmondson@oracle.com>

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

(cherry picked from commit fea4500841024195ec701713e05b92ebf667f192)

   dgilbert: Hairy backport, since we've not got Claudio's cpu

accelerator split

---

 target/i386/cpu.c     | 65 +++++++++++++++++++++++++++++++++++--------

 target/i386/cpu.h     |  2 +-

 target/i386/hvf/hvf.c | 17 ++++-------

 target/i386/kvm.c     |  7 +++++

 4 files changed, 66 insertions(+), 25 deletions(-)

diff --git a/target/i386/cpu.c b/target/i386/cpu.c

index a030030299..c52eae1f0d 100644

--- a/target/i386/cpu.c

+++ b/target/i386/cpu.c

@@ -1504,48 +1504,37 @@ static const X86RegisterInfo32 x86_reg_info_32[CPU_NB_REGS32] = {

 };

 #undef REGISTER

-const ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT] = {

+ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT] = {

     [XSTATE_FP_BIT] = {

         /* x87 FP state component is always enabled if XSAVE is supported */

         .feature = FEAT_1_ECX, .bits = CPUID_EXT_XSAVE,

-        /* x87 state is in the legacy region of the XSAVE area */

-        .offset = 0,

         .size = sizeof(X86LegacyXSaveArea) + sizeof(X86XSaveHeader),

     },

     [XSTATE_SSE_BIT] = {

         /* SSE state component is always enabled if XSAVE is supported */

         .feature = FEAT_1_ECX, .bits = CPUID_EXT_XSAVE,

-        /* SSE state is in the legacy region of the XSAVE area */

-        .offset = 0,

         .size = sizeof(X86LegacyXSaveArea) + sizeof(X86XSaveHeader),

     },

     [XSTATE_YMM_BIT] =

           { .feature = FEAT_1_ECX, .bits = CPUID_EXT_AVX,

-            .offset = offsetof(X86XSaveArea, avx_state),

             .size = sizeof(XSaveAVX) },

     [XSTATE_BNDREGS_BIT] =

           { .feature = FEAT_7_0_EBX, .bits = CPUID_7_0_EBX_MPX,

-            .offset = offsetof(X86XSaveArea, bndreg_state),

             .size = sizeof(XSaveBNDREG)  },

     [XSTATE_BNDCSR_BIT] =

           { .feature = FEAT_7_0_EBX, .bits = CPUID_7_0_EBX_MPX,

-            .offset = offsetof(X86XSaveArea, bndcsr_state),

             .size = sizeof(XSaveBNDCSR)  },

     [XSTATE_OPMASK_BIT] =

           { .feature = FEAT_7_0_EBX, .bits = CPUID_7_0_EBX_AVX512F,

-            .offset = offsetof(X86XSaveArea, opmask_state),

             .size = sizeof(XSaveOpmask) },

     [XSTATE_ZMM_Hi256_BIT] =

           { .feature = FEAT_7_0_EBX, .bits = CPUID_7_0_EBX_AVX512F,

-            .offset = offsetof(X86XSaveArea, zmm_hi256_state),

             .size = sizeof(XSaveZMM_Hi256) },

     [XSTATE_Hi16_ZMM_BIT] =

           { .feature = FEAT_7_0_EBX, .bits = CPUID_7_0_EBX_AVX512F,

-            .offset = offsetof(X86XSaveArea, hi16_zmm_state),

             .size = sizeof(XSaveHi16_ZMM) },

     [XSTATE_PKRU_BIT] =

           { .feature = FEAT_7_0_ECX, .bits = CPUID_7_0_ECX_PKU,

-            .offset = offsetof(X86XSaveArea, pkru_state),

             .size = sizeof(XSavePKRU) },

 };

@@ -5237,6 +5226,52 @@ static void x86_cpu_apply_version_props(X86CPU *cpu, X86CPUModel *model)

     assert(vdef->version == version);

 }

+static void kvm_cpu_xsave_init(void)

+{

+    static bool first = true;

+    KVMState *s = kvm_state;

+    int i;

+

+    if (!first) {

+        return;

+    }

+    first = false;

+

+    /* x87 and SSE states are in the legacy region of the XSAVE area. */

+    x86_ext_save_areas[XSTATE_FP_BIT].offset = 0;

+    x86_ext_save_areas[XSTATE_SSE_BIT].offset = 0;

+

+    for (i = XSTATE_SSE_BIT + 1; i < XSAVE_STATE_AREA_COUNT; i++) {

+        ExtSaveArea *esa = &x86_ext_save_areas[i];

+

+        if (esa->size) {

+            int sz = kvm_arch_get_supported_cpuid(s, 0xd, i, R_EAX);

+            if (sz != 0) {

+                assert(esa->size == sz);

+                esa->offset = kvm_arch_get_supported_cpuid(s, 0xd, i, R_EBX);

+            }

+        }

+    }

+}

+

+static void tcg_cpu_xsave_init(void)

+{

+#define XO(bit, field) \

+    x86_ext_save_areas[bit].offset = offsetof(X86XSaveArea, field);

+

+    XO(XSTATE_FP_BIT, legacy);

+    XO(XSTATE_SSE_BIT, legacy);

+    XO(XSTATE_YMM_BIT, avx_state);

+    XO(XSTATE_BNDREGS_BIT, bndreg_state);

+    XO(XSTATE_BNDCSR_BIT, bndcsr_state);

+    XO(XSTATE_OPMASK_BIT, opmask_state);

+    XO(XSTATE_ZMM_Hi256_BIT, zmm_hi256_state);

+    XO(XSTATE_Hi16_ZMM_BIT, hi16_zmm_state);

+    XO(XSTATE_PKRU_BIT, pkru_state);

+

+#undef XO

+}

+

 /* Load data from X86CPUDefinition into a X86CPU object

  */

 static void x86_cpu_load_model(X86CPU *cpu, X86CPUModel *model, Error **errp)

@@ -7147,6 +7182,12 @@ static void x86_cpu_initfn(Object *obj)

     if (xcc->model) {

         x86_cpu_load_model(cpu, xcc->model, &error_abort);

     }

+

+    if (kvm_enabled()) {

+        kvm_cpu_xsave_init();

+    } else if (tcg_enabled()) {

+        tcg_cpu_xsave_init();

+    }

 }

 static int64_t x86_cpu_get_arch_id(CPUState *cs)

diff --git a/target/i386/cpu.h b/target/i386/cpu.h

index cff2914203..53895a97dd 100644

--- a/target/i386/cpu.h

+++ b/target/i386/cpu.h

@@ -1344,7 +1344,7 @@ typedef struct ExtSaveArea {

 #define XSAVE_STATE_AREA_COUNT (XSTATE_PKRU_BIT + 1)

-extern const ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT];

+extern ExtSaveArea x86_ext_save_areas[XSAVE_STATE_AREA_COUNT];

 typedef enum TPRAccess {

     TPR_ACCESS_READ,

diff --git a/target/i386/hvf/hvf.c b/target/i386/hvf/hvf.c

index bbede52fb7..de29137bec 100644

--- a/target/i386/hvf/hvf.c

+++ b/target/i386/hvf/hvf.c

@@ -612,18 +612,11 @@ int hvf_init_vcpu(CPUState *cpu)

     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);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_CSTAR, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_FMASK, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_FSBASE, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_GSBASE, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_KERNELGSBASE, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_TSC_AUX, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_IA32_TSC, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_IA32_SYSENTER_CS, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_IA32_SYSENTER_EIP, 1);

-    hv_vcpu_enable_native_msr(cpu->hvf_fd, MSR_IA32_SYSENTER_ESP, 1);

+    /*

+     * The allocated storage must be large enough for all of the

+     * possible XSAVE state components.

+     */

+    assert(hvf_get_supported_cpuid(0xd, 0, R_ECX) <= x86cpu->env.xsave_buf_len);

     return 0;

 }

diff --git a/target/i386/kvm.c b/target/i386/kvm.c

index 8167587445..548c5e94bb 100644

--- a/target/i386/kvm.c

+++ b/target/i386/kvm.c

@@ -1829,6 +1829,13 @@ int kvm_arch_init_vcpu(CPUState *cs)

         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);

+

+        /*

+         * The allocated storage must be large enough for all of the

+         * possible XSAVE state components.

+         */

+        assert(kvm_arch_get_supported_cpuid(kvm_state, 0xd, 0, R_ECX)

+               <= env->xsave_buf_len);

     }

     max_nested_state_len = kvm_max_nested_state_length();

-- 

2.27.0