[Xen-devel] [v3 05/10] vmx: add help functions to support PML

[Kai Huang <kai.huang@xxxxxxxxxxxxxxx>]

This patch adds help functions to enable/disable PML, and flush PML buffer for
single vcpu and particular domain for further use.

Signed-off-by: Kai Huang <kai.huang@xxxxxxxxxxxxxxx>
---
 xen/arch/x86/hvm/vmx/vmcs.c        | 179 +++++++++++++++++++++++++++++++++++++
 xen/include/asm-x86/hvm/vmx/vmcs.h |   9 ++
 2 files changed, 188 insertions(+)

diff --git a/xen/arch/x86/hvm/vmx/vmcs.c b/xen/arch/x86/hvm/vmx/vmcs.c
index 04fdca3..f797fde 100644
--- a/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen/arch/x86/hvm/vmx/vmcs.c
@@ -1323,6 +1323,185 @@ void vmx_clear_eoi_exit_bitmap(struct vcpu *v, u8 
vector)
                 &v->arch.hvm_vmx.eoi_exitmap_changed);
 }
 
+bool_t vmx_vcpu_pml_enabled(const struct vcpu *v)
+{
+    return !!(v->arch.hvm_vmx.secondary_exec_control &
+              SECONDARY_EXEC_ENABLE_PML);
+}
+
+int vmx_vcpu_enable_pml(struct vcpu *v)
+{
+    if ( vmx_vcpu_pml_enabled(v) )
+        return 0;
+
+    v->arch.hvm_vmx.pml_pg = v->domain->arch.paging.alloc_page(v->domain);
+    if ( !v->arch.hvm_vmx.pml_pg )
+        return -ENOMEM;
+
+    vmx_vmcs_enter(v);
+
+    __vmwrite(PML_ADDRESS, page_to_mfn(v->arch.hvm_vmx.pml_pg) << PAGE_SHIFT);
+    __vmwrite(GUEST_PML_INDEX, NR_PML_ENTRIES - 1);
+
+    v->arch.hvm_vmx.secondary_exec_control |= SECONDARY_EXEC_ENABLE_PML;
+
+    __vmwrite(SECONDARY_VM_EXEC_CONTROL,
+              v->arch.hvm_vmx.secondary_exec_control);
+
+    vmx_vmcs_exit(v);
+
+    return 0;
+}
+
+void vmx_vcpu_disable_pml(struct vcpu *v)
+{
+    if ( !vmx_vcpu_pml_enabled(v) )
+        return;
+
+    /* Make sure we don't lose any logged GPAs */
+    vmx_vcpu_flush_pml_buffer(v);
+
+    vmx_vmcs_enter(v);
+
+    v->arch.hvm_vmx.secondary_exec_control &= ~SECONDARY_EXEC_ENABLE_PML;
+    __vmwrite(SECONDARY_VM_EXEC_CONTROL,
+              v->arch.hvm_vmx.secondary_exec_control);
+
+    vmx_vmcs_exit(v);
+
+    v->domain->arch.paging.free_page(v->domain, v->arch.hvm_vmx.pml_pg);
+    v->arch.hvm_vmx.pml_pg = NULL;
+}
+
+void vmx_vcpu_flush_pml_buffer(struct vcpu *v)
+{
+    uint64_t *pml_buf;
+    unsigned long pml_idx;
+
+    ASSERT((v == current) || (!vcpu_runnable(v) && !v->is_running));
+    ASSERT(vmx_vcpu_pml_enabled(v));
+
+    vmx_vmcs_enter(v);
+
+    __vmread(GUEST_PML_INDEX, &pml_idx);
+
+    /* Do nothing if PML buffer is empty */
+    if ( pml_idx == (NR_PML_ENTRIES - 1) )
+        goto out;
+
+    pml_buf = __map_domain_page(v->arch.hvm_vmx.pml_pg);
+
+    /*
+     * PML index can be either 2^16-1 (buffer is full), or 0 ~ NR_PML_ENTRIES-1
+     * (buffer is not full), and in latter case PML index always points to next
+     * available entity.
+     */
+    if (pml_idx >= NR_PML_ENTRIES)
+        pml_idx = 0;
+    else
+        pml_idx++;
+
+    for ( ; pml_idx < NR_PML_ENTRIES; pml_idx++ )
+    {
+        unsigned long gfn = pml_buf[pml_idx] >> PAGE_SHIFT;
+
+        /*
+         * Need to change type from log-dirty to normal memory for logged GFN.
+         * hap_track_dirty_vram depends on it to work. And we mark all logged
+         * GFNs to be dirty, as we cannot be sure whether it's safe to ignore
+         * GFNs on which p2m_change_type_one returns failure. The failure cases
+         * are very rare, and additional cost is negligible, but a missing mark
+         * is extremely difficult to debug.
+         */
+        p2m_change_type_one(v->domain, gfn, p2m_ram_logdirty, p2m_ram_rw);
+        paging_mark_gfn_dirty(v->domain, gfn);
+    }
+
+    unmap_domain_page(pml_buf);
+
+    /* Reset PML index */
+    __vmwrite(GUEST_PML_INDEX, NR_PML_ENTRIES - 1);
+
+ out:
+    vmx_vmcs_exit(v);
+}
+
+bool_t vmx_domain_pml_enabled(const struct domain *d)
+{
+    return !!(d->arch.hvm_domain.vmx.status & VMX_DOMAIN_PML_ENABLED);
+}
+
+/*
+ * This function enables PML for particular domain. It should be called when
+ * domain is paused.
+ *
+ * PML needs to be enabled globally for all vcpus of the domain, as PML buffer
+ * and PML index are pre-vcpu, but EPT table is shared by vcpus, therefore
+ * enabling PML on partial vcpus won't work.
+ */
+int vmx_domain_enable_pml(struct domain *d)
+{
+    struct vcpu *v;
+    int rc;
+
+    ASSERT(atomic_read(&d->pause_count));
+
+    if ( vmx_domain_pml_enabled(d) )
+        return 0;
+
+    for_each_vcpu( d, v )
+        if ( (rc = vmx_vcpu_enable_pml(v)) != 0 )
+            goto error;
+
+    d->arch.hvm_domain.vmx.status |= VMX_DOMAIN_PML_ENABLED;
+
+    return 0;
+
+ error:
+    for_each_vcpu( d, v )
+        if ( vmx_vcpu_pml_enabled(v) )
+            vmx_vcpu_disable_pml(v);
+    return rc;
+}
+
+/*
+ * Disable PML for particular domain. Called when domain is paused.
+ *
+ * The same as enabling PML for domain, disabling PML should be done for all
+ * vcpus at once.
+ */
+void vmx_domain_disable_pml(struct domain *d)
+{
+    struct vcpu *v;
+
+    ASSERT(atomic_read(&d->pause_count));
+
+    if ( !vmx_domain_pml_enabled(d) )
+        return;
+
+    for_each_vcpu( d, v )
+        vmx_vcpu_disable_pml(v);
+
+    d->arch.hvm_domain.vmx.status &= ~VMX_DOMAIN_PML_ENABLED;
+}
+
+/*
+ * Flush PML buffer of all vcpus, and update the logged dirty pages to 
log-dirty
+ * radix tree. Called when domain is paused.
+ */
+void vmx_domain_flush_pml_buffers(struct domain *d)
+{
+    struct vcpu *v;
+
+    ASSERT(atomic_read(&d->pause_count));
+
+    if ( !vmx_domain_pml_enabled(d) )
+        return;
+
+    for_each_vcpu( d, v )
+        vmx_vcpu_flush_pml_buffer(v);
+}
+
 int vmx_create_vmcs(struct vcpu *v)
 {
     struct arch_vmx_struct *arch_vmx = &v->arch.hvm_vmx;
diff --git a/xen/include/asm-x86/hvm/vmx/vmcs.h 
b/xen/include/asm-x86/hvm/vmx/vmcs.h
index 441e974..6c13dbb 100644
--- a/xen/include/asm-x86/hvm/vmx/vmcs.h
+++ b/xen/include/asm-x86/hvm/vmx/vmcs.h
@@ -499,6 +499,15 @@ static inline int vmx_add_host_load_msr(u32 msr)
 
 DECLARE_PER_CPU(bool_t, vmxon);
 
+bool_t vmx_vcpu_pml_enabled(const struct vcpu *v);
+int vmx_vcpu_enable_pml(struct vcpu *v);
+void vmx_vcpu_disable_pml(struct vcpu *v);
+void vmx_vcpu_flush_pml_buffer(struct vcpu *v);
+bool_t vmx_domain_pml_enabled(const struct domain *d);
+int vmx_domain_enable_pml(struct domain *d);
+void vmx_domain_disable_pml(struct domain *d);
+void vmx_domain_flush_pml_buffers(struct domain *d);
+
 #endif /* ASM_X86_HVM_VMX_VMCS_H__ */
 
 /*
-- 
2.1.0


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