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hv: nested: Manage shadow EPTP according to guest VMCS change

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'struct nept_desc' is used to associate guest EPTP with a shadow EPTP.
It's created in the first reference and be freed while no reference.

The life cycle seems like,

While guest VMCS VMX_EPT_POINTER_FULL is changed, the 'struct nept_desc'
of the new guest EPTP is referenced; the 'struct nept_desc' of the old
guest EPTP is dereferenced.

While guest VMCS be cleared(by VMCLEAR in L1 VM), the 'struct nept_desc'
of the old guest EPTP is dereferenced.

While a new guest VMCS be loaded(by VMPTRLD in L1 VM), the 'struct
nept_desc' of the new guest EPTP is referenced. The 'struct nept_desc'
of the old guest EPTP is dereferenced.

Tracked-On: #5923
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: Zide Chen <zide.chen@intel.com>
Signed-off-by: Shuo A Liu <shuo.a.liu@intel.com>
Reviewed-by: Jason Chen CJ <jason.cj.chen@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>
This commit is contained in:
Shuo A Liu 2021-05-27 14:18:27 +08:00 committed by Xie, Nanlin
parent 10ec896f99
commit 540a484147
3 changed files with 35 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
hypervisor/arch/x86/guest/nested.c
View File

@ -229,7 +229,7 @@ int32_t read_vmx_msr(struct acrn_vcpu *vcpu, uint32_t msr, uint64_t *val)
return err;
}
#define MAX_SHADOW_VMCS_FIELDS 115U
#define MAX_SHADOW_VMCS_FIELDS 114U
/*
* VMCS fields included in the dual-purpose VMCS: as shadow for L1 and
* as hardware VMCS for nested guest (L2).
@ -267,7 +267,6 @@ static const uint32_t vmcs_shadowing_fields[MAX_SHADOW_VMCS_FIELDS] = {
VMX_TSC_OFFSET_FULL,
VMX_VIRTUAL_APIC_PAGE_ADDR_FULL,
VMX_APIC_ACCESS_ADDR_FULL,
VMX_EPT_POINTER_FULL,
VMX_VMREAD_BITMAP_FULL,
VMX_VMWRITE_BITMAP_FULL,
VMX_XSS_EXITING_BITMAP_FULL,
@ -871,8 +870,16 @@ int32_t vmwrite_vmexit_handler(struct acrn_vcpu *vcpu)
* For simplicity, gpa_field_dirty could be used for all VMCS fields that
* are programmed by L1 hypervisor with a GPA address
*/
if (vmcs_field == VMX_MSR_BITMAP_FULL) {
if ((vmcs_field == VMX_MSR_BITMAP_FULL) ||
(vmcs_field == VMX_EPT_POINTER_FULL)) {
vcpu->arch.nested.gpa_field_dirty = true;
if (vmcs_field == VMX_EPT_POINTER_FULL) {
if (vcpu->arch.nested.vmcs12.ept_pointer != vmcs_value) {
put_nept_desc(vcpu->arch.nested.vmcs12.ept_pointer);
get_nept_desc(vmcs_value);
}
}
}
if ((vmcs_field == VMX_ENTRY_CONTROLS)
@ -1088,6 +1095,8 @@ int32_t vmptrld_vmexit_handler(struct acrn_vcpu *vcpu)
* needs to be VMCLEARed as well
*/
clear_va_vmcs(nested->vmcs02);
put_nept_desc(nested->vmcs12.ept_pointer);
}
/* Create the VMCS02 based on this new VMCS12 */
@ -1111,9 +1120,11 @@ int32_t vmptrld_vmexit_handler(struct acrn_vcpu *vcpu)
/* Load VMCS12 from L1 guest memory */
(void)copy_from_gpa(vcpu->vm, (void *)&nested->vmcs12, vmcs12_gpa,
sizeof(struct acrn_vmcs12));
vcpu->arch.nested.gpa_field_dirty = true;
/* Need to load shadow fields from this new VMCS12 to VMCS02 */
sync_vmcs12_to_vmcs02(vcpu);
get_nept_desc(nested->vmcs12.ept_pointer);
/* Before VMCS02 is being used as a shadow VMCS, VMCLEAR it */
clear_va_vmcs(nested->vmcs02);
@ -1183,6 +1194,9 @@ int32_t vmclear_vmexit_handler(struct acrn_vcpu *vcpu)
/* Switch back to vmcs01 (no VMCS shadowing) */
load_va_vmcs(vcpu->arch.vmcs);
/* This VMCS can no longer refer to any shadow EPT */
put_nept_desc(nested->vmcs12.ept_pointer);
/* no current VMCS12 */
nested->current_vmcs12_ptr = INVALID_GPA;
@ -1335,8 +1349,13 @@ static void set_vmcs01_guest_state(struct acrn_vcpu *vcpu)
int32_t nested_vmexit_handler(struct acrn_vcpu *vcpu)
{
struct acrn_vmcs12 *vmcs12 = (struct acrn_vmcs12 *)&vcpu->arch.nested.vmcs12;
bool reflect_to_l1 = true;
if (reflect_to_l1) {
bool is_l1_vmexit = true;
if ((exec_vmread(VMX_EXIT_REASON) & 0xFFFFU) == VMX_EXIT_REASON_EPT_VIOLATION) {
is_l1_vmexit = handle_l2_ept_violation(vcpu);
}
if (is_l1_vmexit) {
/*
* Currerntly VMX_VPID is shadowing to L1, so we flush L2 VPID before
* L1 VM entry to avoid conflicting with L1 VPID.
@ -1384,6 +1403,7 @@ static void merge_and_sync_control_fields(struct acrn_vcpu *vcpu)
if (vcpu->arch.nested.gpa_field_dirty) {
vcpu->arch.nested.gpa_field_dirty = false;
exec_vmwrite(VMX_MSR_BITMAP_FULL, gpa2hpa(vcpu->vm, vmcs12->msr_bitmap));
exec_vmwrite(VMX_EPT_POINTER_FULL, get_shadow_eptp(vmcs12->ept_pointer));
}
/* for VM-execution, VM-exit, VM-entry control fields */

9
hypervisor/arch/x86/guest/vept.c
View File

@ -160,6 +160,15 @@ void put_nept_desc(uint64_t guest_eptp)
}
}
/**
* @pre vcpu != NULL
*/
bool handle_l2_ept_violation(__unused struct acrn_vcpu *vcpu)
{
/* TODO: Construct the shadow page table for EPT violation address */
return true;
}
/**
* @pre vcpu != NULL
*/

1
hypervisor/include/arch/x86/asm/guest/vept.h
View File

@ -31,6 +31,7 @@ void init_vept(void);
uint64_t get_shadow_eptp(uint64_t guest_eptp);
struct nept_desc *get_nept_desc(uint64_t guest_eptp);
void put_nept_desc(uint64_t guest_eptp);
bool handle_l2_ept_violation(struct acrn_vcpu *vcpu);
int32_t invept_vmexit_handler(struct acrn_vcpu *vcpu);
#else
static inline void reserve_buffer_for_sept_pages(void) {};