[PATCH v5 7/7] kvm, mem-hotplug: Unpin and remove nested_vmx->apic_access_page.

Tang Chen
2014-09-11T05:37:21Z

Just like we removed kvm_arch->apic_access_page, nested_vmx->apic_access_page
becomes useless for the same reason. This patch removes nested_vmx->apic_access_page,
and use gfn_to_page() to pin it in memory when we need it, and unpin it after then.

Signed-off-by: Tang Chen <tangchen@cn.fujitsu.com>
---
arch/x86/kvm/vmx.c | 31 +++++++++----------------------
1 file changed, 9 insertions(+), 22 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 058c373..4aa73cb 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -374,11 +374,6 @@ struct nested_vmx {
u64 vmcs01_tsc_offset;
/* L2 must run next, and mustn't decide to exit to L1. */
bool nested_run_pending;
- /*
- * Guest pages referred to in vmcs02 with host-physical pointers, so
- * we must keep them pinned while L2 runs.
- */
- struct page *apic_access_page;
u64 msr_ia32_feature_control;

struct hrtimer preemption_timer;
@@ -6154,11 +6149,6 @@ static void free_nested(struct vcpu_vmx *vmx)
nested_release_vmcs12(vmx);
if (enable_shadow_vmcs)
free_vmcs(vmx->nested.current_shadow_vmcs);
- /* Unpin physical memory we referred to in current vmcs02 */
- if (vmx->nested.apic_access_page) {
- nested_release_page(vmx->nested.apic_access_page);
- vmx->nested.apic_access_page = 0;
- }

nested_free_all_saved_vmcss(vmx);
}
@@ -7983,28 +7973,31 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12)
exec_control |= vmcs12->secondary_vm_exec_control;

if (exec_control & SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES) {
+ struct page *page;
/*
* Translate L1 physical address to host physical
* address for vmcs02. Keep the page pinned, so this
* physical address remains valid. We keep a reference
* to it so we can release it later.
*/
- if (vmx->nested.apic_access_page) /* shouldn't happen */
- nested_release_page(vmx->nested.apic_access_page);
- vmx->nested.apic_access_page =
- nested_get_page(vcpu, vmcs12->apic_access_addr);
+ page = nested_get_page(vcpu, vmcs12->apic_access_addr);
/*
* If translation failed, no matter: This feature asks
* to exit when accessing the given address, and if it
* can never be accessed, this feature won't do
* anything anyway.
*/
- if (!vmx->nested.apic_access_page)
+ if (!page)
exec_control &=
~SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES;
else
vmcs_write64(APIC_ACCESS_ADDR,
- page_to_phys(vmx->nested.apic_access_page));
+ page_to_phys(page));
+ /*
+ * Do not pin nested vm's apic access page in memory so
+ * that memory hotplug process is able to migrate it.
+ */
+ put_page(page);
} else if (vm_need_virtualize_apic_accesses(vmx->vcpu.kvm)) {
struct page *page = gfn_to_page(vmx->vcpu.kvm,
APIC_DEFAULT_PHYS_BASE >> PAGE_SHIFT);
@@ -8807,12 +8800,6 @@ static void nested_vmx_vmexit(struct kvm_vcpu *vcpu, u32 exit_reason,
/* This is needed for same reason as it was needed in prepare_vmcs02 */
vmx->host_rsp = 0;

- /* Unpin physical memory we referred to in vmcs02 */
- if (vmx->nested.apic_access_page) {
- nested_release_page(vmx->nested.apic_access_page);
- vmx->nested.apic_access_page = 0;
- }
-
/*
* Do not call kvm_reload_apic_access_page() because we are now
* running, mmu_notifier will force to reload the page's hpa for L2
--
1.8.3.1