[PATCH][RFC] FPU LWP 4/5: enable LWP for SVM guest

[Wei Huang <wei.huang2@amd.com>]

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This patch enables LWP support for SVM guests. It saves and restores 
LWP_CFG MSRs on each VCPU context switch. Additionally it handles LWP 
CPUIDs and MSRs.

Signed-off-by: Wei Huang <wei.huang2@amd.com>


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# HG changeset patch
# User Wei Huang <wei.huang2@amd.com>
# Date 1302812238 18000
# Branch lwp3
# Node ID ee8656e10937121d2780862351a245ed874273fa
# Parent  bccbc5ecf62e49482c06149bb94dfc3dee8882f1
SVM: enable LWP for SVM guest

This patch enables LWP support for SVM guests. It saves and restores LWP_CFG MSRs on each VCPU context switch. Additionally it handles LWP CPUIDs and MSRs.

Signed-off-by: Wei Huang <wei.huang2@amd.com>

diff -r bccbc5ecf62e -r ee8656e10937 xen/arch/x86/hvm/svm/svm.c
--- a/xen/arch/x86/hvm/svm/svm.c	Thu Apr 14 15:15:36 2011 -0500
+++ b/xen/arch/x86/hvm/svm/svm.c	Thu Apr 14 15:17:18 2011 -0500
@@ -680,6 +680,26 @@
     *(u16 *)(hypercall_page + (__HYPERVISOR_iret * 32)) = 0x0b0f; /* ud2 */
 }
 
+static void svm_lwp_save(struct vcpu *v)
+{
+    if ( cpu_has_lwp )
+    {
+        rdmsrl(MSR_AMD64_LWP_CFG, v->arch.hvm_svm.guest_lwp_cfg);
+        wrmsrl(MSR_AMD64_LWP_CFG, 0x0);
+        /* Disable LWP for next VCPU */
+        wrmsrl(MSR_AMD64_LWP_CBADDR, 0x0);
+    }
+}
+
+static void svm_lwp_load(struct vcpu *v)
+{
+    if ( cpu_has_lwp ) 
+    {
+        /* Only LWP_CFG is reloaded. LWP_CBADDR will be reloaded via xrstor */
+        wrmsrl(MSR_AMD64_LWP_CFG, v->arch.hvm_svm.guest_lwp_cfg);
+    }
+}
+
 static void svm_ctxt_switch_from(struct vcpu *v)
 {
     int cpu = smp_processor_id();
@@ -688,6 +708,7 @@
 
     svm_save_dr(v);
     vpmu_save(v);
+    svm_lwp_save(v);
 
     svm_sync_vmcb(v);
     svm_vmload(per_cpu(root_vmcb, cpu));
@@ -731,6 +752,7 @@
     svm_vmload(vmcb);
     vmcb->cleanbits.bytes = 0;
     vpmu_load(v);
+    svm_lwp_load(v);
 
     if ( cpu_has_rdtscp )
         wrmsrl(MSR_TSC_AUX, hvm_msr_tsc_aux(v));
@@ -1100,6 +1122,24 @@
         if ( vlapic_hw_disabled(vcpu_vlapic(v)) )
             __clear_bit(X86_FEATURE_APIC & 31, edx);
         break;
+    case 0x8000001c: 
+    {
+        /* LWP capability CPUID */
+        uint64_t lwp_cfg = v->arch.hvm_svm.guest_lwp_cfg;
+
+        if ( cpu_has_lwp )
+        {
+            if ( !(v->arch.xcr0 & XSTATE_LWP) )
+            {
+                *eax = 0x0;
+                break;
+            }
+
+            /* turn on avail bit and other features specified in lwp_cfg */
+            *eax = (*edx & lwp_cfg) | 0x00000001;
+        }
+        break;
+    }
     default:
         break;
     }
@@ -1189,6 +1229,10 @@
 
     case MSR_IA32_LASTINTTOIP:
         *msr_content = vmcb_get_lastinttoip(vmcb);
+        break;
+        
+    case MSR_AMD64_LWP_CFG:
+        *msr_content = v->arch.hvm_svm.guest_lwp_cfg;
         break;
 
     case MSR_K7_PERFCTR0:
@@ -1287,6 +1331,24 @@
 
     case MSR_IA32_LASTINTTOIP:
         vmcb_set_lastinttoip(vmcb, msr_content);
+        break;
+
+    case MSR_AMD64_LWP_CFG:
+        if ( cpu_has_lwp )
+        {
+            unsigned int eax, ebx, ecx, edx;
+            uint32_t msr_low;
+
+            hvm_cpuid(0x8000001c, &eax, &ebx, &ecx, &edx);
+            msr_low = (uint32_t)msr_content;
+
+            /* generate #GP if guest triest to turn on unsupported features. */
+            if ( msr_low & ~edx)
+                goto gpf;
+
+            wrmsrl(msr, msr_content);
+            v->arch.hvm_svm.guest_lwp_cfg = msr_content;
+        }
         break;
 
     case MSR_K7_PERFCTR0:
diff -r bccbc5ecf62e -r ee8656e10937 xen/arch/x86/hvm/svm/vmcb.c
--- a/xen/arch/x86/hvm/svm/vmcb.c	Thu Apr 14 15:15:36 2011 -0500
+++ b/xen/arch/x86/hvm/svm/vmcb.c	Thu Apr 14 15:17:18 2011 -0500
@@ -120,6 +120,8 @@
     svm_disable_intercept_for_msr(v, MSR_LSTAR);
     svm_disable_intercept_for_msr(v, MSR_STAR);
     svm_disable_intercept_for_msr(v, MSR_SYSCALL_MASK);
+    if ( cpu_has_lwp)
+        svm_disable_intercept_for_msr(v, MSR_AMD64_LWP_CBADDR);
 
     vmcb->_msrpm_base_pa = (u64)virt_to_maddr(arch_svm->msrpm);
     vmcb->_iopm_base_pa  = (u64)virt_to_maddr(hvm_io_bitmap);
diff -r bccbc5ecf62e -r ee8656e10937 xen/include/asm-x86/cpufeature.h
--- a/xen/include/asm-x86/cpufeature.h	Thu Apr 14 15:15:36 2011 -0500
+++ b/xen/include/asm-x86/cpufeature.h	Thu Apr 14 15:17:18 2011 -0500
@@ -208,6 +208,8 @@
 
 #define cpu_has_xsave           boot_cpu_has(X86_FEATURE_XSAVE)
 
+#define cpu_has_lwp             boot_cpu_has(X86_FEATURE_LWP)
+
 #define cpu_has_arch_perfmon    boot_cpu_has(X86_FEATURE_ARCH_PERFMON)
 
 #define cpu_has_rdtscp          boot_cpu_has(X86_FEATURE_RDTSCP)
diff -r bccbc5ecf62e -r ee8656e10937 xen/include/asm-x86/hvm/svm/vmcb.h
--- a/xen/include/asm-x86/hvm/svm/vmcb.h	Thu Apr 14 15:15:36 2011 -0500
+++ b/xen/include/asm-x86/hvm/svm/vmcb.h	Thu Apr 14 15:17:18 2011 -0500
@@ -507,6 +507,9 @@
     uint64_t guest_sysenter_cs;
     uint64_t guest_sysenter_esp;
     uint64_t guest_sysenter_eip;
+
+    /* AMD lightweight profiling MSR */
+    uint64_t guest_lwp_cfg;
 };
 
 struct vmcb_struct *alloc_vmcb(void);
diff -r bccbc5ecf62e -r ee8656e10937 xen/include/asm-x86/msr-index.h
--- a/xen/include/asm-x86/msr-index.h	Thu Apr 14 15:15:36 2011 -0500
+++ b/xen/include/asm-x86/msr-index.h	Thu Apr 14 15:17:18 2011 -0500
@@ -253,6 +253,10 @@
 #define MSR_AMD_PATCHLEVEL		0x0000008b
 #define MSR_AMD_PATCHLOADER		0xc0010020
 
+/* AMD Lightweight Profiling MSRs */
+#define MSR_AMD64_LWP_CFG                 0xc0000105
+#define MSR_AMD64_LWP_CBADDR              0xc0000106
+
 /* AMD OS Visible Workaround MSRs */
 #define MSR_AMD_OSVW_ID_LENGTH          0xc0010140
 #define MSR_AMD_OSVW_STATUS             0xc0010141

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