On Wed, Jul 19, 2023, Binbin Wu wrote:
> Untag address for 64-bit memory operand in VMExit handlers when LAM is applicable.
>
> For VMExit handlers related to 64-bit linear address:
> - Cases need to untag address (handled in get_vmx_mem_address())
> Operand(s) of VMX instructions and INVPCID.
> Operand(s) of SGX ENCLS.
> - Cases LAM doesn't apply to (no change needed)
> Operand of INVLPG.
> Linear address in INVPCID descriptor.
> Linear address in INVVPID descriptor.
> BASEADDR specified in SESC of ECREATE.
>
> Note:
> LAM doesn't apply to the writes to control registers or MSRs.
> LAM masking applies before paging, so the faulting linear address in CR2
> doesn't contain the metadata.
> The guest linear address saved in VMCS doesn't contain metadata.
>
> Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx>
> Reviewed-by: Chao Gao <chao.gao@xxxxxxxxx>
> ---
> arch/x86/kvm/vmx/nested.c | 2 ++
> arch/x86/kvm/vmx/sgx.c | 1 +
> arch/x86/kvm/vmx/vmx.c | 3 +--
> arch/x86/kvm/vmx/vmx.h | 2 ++
> arch/x86/kvm/x86.c | 1 +
> 5 files changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
> index 76c9904c6625..bd2c8936953a 100644
> --- a/arch/x86/kvm/vmx/nested.c
> +++ b/arch/x86/kvm/vmx/nested.c
> @@ -4980,6 +4980,7 @@ int get_vmx_mem_address(struct kvm_vcpu *vcpu, unsigned long exit_qualification,
> else
> *ret = off;
>
> + *ret = vmx_get_untagged_addr(vcpu, *ret, 0);
> /* Long mode: #GP(0)/#SS(0) if the memory address is in a
> * non-canonical form. This is the only check on the memory
> * destination for long mode!
> @@ -5797,6 +5798,7 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
> vpid02 = nested_get_vpid02(vcpu);
> switch (type) {
> case VMX_VPID_EXTENT_INDIVIDUAL_ADDR:
> + /* LAM doesn't apply to the address in descriptor of invvpid */
Nit, if we're going to bother with a comment, I think it makes sense to explain
that LAM doesn't apply to any TLB invalidation input, i.e. as opposed to just
saying the INVVPID is special.
/*
* LAM doesn't apply to addresses that are inputs to TLB
* invalidation.
*/
And then when LAM and LASS collide:
/*
* LAM and LASS don't apply to ...
*/
> if (!operand.vpid ||
> is_noncanonical_address(operand.gla, vcpu))
> return nested_vmx_fail(vcpu,
> diff --git a/arch/x86/kvm/vmx/sgx.c b/arch/x86/kvm/vmx/sgx.c
> index 3e822e582497..6fef01e0536e 100644
> --- a/arch/x86/kvm/vmx/sgx.c
> +++ b/arch/x86/kvm/vmx/sgx.c
> @@ -37,6 +37,7 @@ static int sgx_get_encls_gva(struct kvm_vcpu *vcpu, unsigned long offset,
> if (!IS_ALIGNED(*gva, alignment)) {
> fault = true;
> } else if (likely(is_64_bit_mode(vcpu))) {
> + *gva = vmx_get_untagged_addr(vcpu, *gva, 0);
> fault = is_noncanonical_address(*gva, vcpu);
> } else {
> *gva &= 0xffffffff;
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index abf6d42672cd..f18e610c4363 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -8177,8 +8177,7 @@ static void vmx_vm_destroy(struct kvm *kvm)
> free_pages((unsigned long)kvm_vmx->pid_table, vmx_get_pid_table_order(kvm));
> }
>
> -static gva_t vmx_get_untagged_addr(struct kvm_vcpu *vcpu, gva_t gva,
> - unsigned int flags)
> +gva_t vmx_get_untagged_addr(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags)
> {
> unsigned long cr3_bits;
> int lam_bit;
> diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
> index 32384ba38499..6fb612355769 100644
> --- a/arch/x86/kvm/vmx/vmx.h
> +++ b/arch/x86/kvm/vmx/vmx.h
> @@ -421,6 +421,8 @@ void vmx_enable_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr, int type);
> u64 vmx_get_l2_tsc_offset(struct kvm_vcpu *vcpu);
> u64 vmx_get_l2_tsc_multiplier(struct kvm_vcpu *vcpu);
>
> +gva_t vmx_get_untagged_addr(struct kvm_vcpu *vcpu, gva_t gva, unsigned int flags);
> +
> static inline void vmx_set_intercept_for_msr(struct kvm_vcpu *vcpu, u32 msr,
> int type, bool value)
> {
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 339a113b45af..d2a0cdfb77a5 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -13370,6 +13370,7 @@ int kvm_handle_invpcid(struct kvm_vcpu *vcpu, unsigned long type, gva_t gva)
>
> switch (type) {
> case INVPCID_TYPE_INDIV_ADDR:
> + /* LAM doesn't apply to the address in descriptor of invpcid */
Same thing here.
> if ((!pcid_enabled && (operand.pcid != 0)) ||
> is_noncanonical_address(operand.gla, vcpu)) {
> kvm_inject_gp(vcpu, 0);
> --
> 2.25.1
>
