[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v1 2/3] x86/vvmx: correct nested shadow VMCS handling
Currently xen always sets the shadow VMCS-indicator bit on nested vmptrld and always clears it on nested vmclear. This behavior is wrong when the guest loads a shadow VMCS: shadow bit will be lost on nested vmclear. Fix this by checking if the guest has provided a shadow VMCS. Signed-off-by: Sergey Dyasli <sergey.dyasli@xxxxxxxxxx> --- xen/arch/x86/hvm/vmx/vvmx.c | 22 ++++++++++++++++++---- xen/include/asm-x86/hvm/vmx/vvmx.h | 1 + 2 files changed, 19 insertions(+), 4 deletions(-) diff --git a/xen/arch/x86/hvm/vmx/vvmx.c b/xen/arch/x86/hvm/vmx/vvmx.c index 09e4250..3017849 100644 --- a/xen/arch/x86/hvm/vmx/vvmx.c +++ b/xen/arch/x86/hvm/vmx/vvmx.c @@ -1119,10 +1119,19 @@ static bool_t nvmx_vpid_enabled(const struct vcpu *v) static void nvmx_set_vmcs_pointer(struct vcpu *v, struct vmcs_struct *vvmcs) { + struct nestedvmx *nvmx = &vcpu_2_nvmx(v); paddr_t vvmcs_maddr = v->arch.hvm_vmx.vmcs_shadow_maddr; __vmpclear(vvmcs_maddr); - vvmcs->vmcs_revision_id |= VMCS_RID_TYPE_MASK; + if ( !nvmx->shadow_vmcs ) + { + /* + * We must set the shadow VMCS-indicator in order for the next vmentry + * to succeed with a newly set up link pointer in vmcs01. + * Note: guest can see that this bit was set. + */ + vvmcs->vmcs_revision_id |= VMCS_RID_TYPE_MASK; + } __vmwrite(VMCS_LINK_POINTER, vvmcs_maddr); __vmwrite(VMREAD_BITMAP, page_to_maddr(v->arch.hvm_vmx.vmread_bitmap)); __vmwrite(VMWRITE_BITMAP, page_to_maddr(v->arch.hvm_vmx.vmwrite_bitmap)); @@ -1130,10 +1139,13 @@ static void nvmx_set_vmcs_pointer(struct vcpu *v, struct vmcs_struct *vvmcs) static void nvmx_clear_vmcs_pointer(struct vcpu *v, struct vmcs_struct *vvmcs) { + struct nestedvmx *nvmx = &vcpu_2_nvmx(v); paddr_t vvmcs_maddr = v->arch.hvm_vmx.vmcs_shadow_maddr; __vmpclear(vvmcs_maddr); - vvmcs->vmcs_revision_id &= ~VMCS_RID_TYPE_MASK; + if ( !nvmx->shadow_vmcs ) + vvmcs->vmcs_revision_id &= ~VMCS_RID_TYPE_MASK; + nvmx->shadow_vmcs = false; __vmwrite(VMCS_LINK_POINTER, ~0ul); __vmwrite(VMREAD_BITMAP, 0); __vmwrite(VMWRITE_BITMAP, 0); @@ -1674,12 +1686,14 @@ int nvmx_handle_vmptrld(struct cpu_user_regs *regs) { if ( writable ) { + struct nestedvmx *nvmx = &vcpu_2_nvmx(v); struct vmcs_struct *vvmcs = vvmcx; + nvmx->shadow_vmcs = + vvmcs->vmcs_revision_id & ~VMX_BASIC_REVISION_MASK; if ( ((vvmcs->vmcs_revision_id ^ vmx_basic_msr) & VMX_BASIC_REVISION_MASK) || - (!cpu_has_vmx_vmcs_shadowing && - (vvmcs->vmcs_revision_id & ~VMX_BASIC_REVISION_MASK)) ) + (!cpu_has_vmx_vmcs_shadowing && nvmx->shadow_vmcs) ) { hvm_unmap_guest_frame(vvmcx, 1); vmfail(regs, VMX_INSN_VMPTRLD_INCORRECT_VMCS_ID); diff --git a/xen/include/asm-x86/hvm/vmx/vvmx.h b/xen/include/asm-x86/hvm/vmx/vvmx.h index ca2fb25..9a65218 100644 --- a/xen/include/asm-x86/hvm/vmx/vvmx.h +++ b/xen/include/asm-x86/hvm/vmx/vvmx.h @@ -51,6 +51,7 @@ struct nestedvmx { } ept; uint32_t guest_vpid; struct list_head launched_list; + bool shadow_vmcs; }; #define vcpu_2_nvmx(v) (vcpu_nestedhvm(v).u.nvmx) -- 2.9.3 _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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