Re: [PATCH v7 4/5] KVM: x86: Untag address when LAM applicable

[Chao Gao <chao.gao@intel.com>]

On Tue, Apr 04, 2023 at 09:09:22PM +0800, Binbin Wu wrote:
>Untag address for 64-bit memory/mmio operand in instruction emulations
>and vmexit handlers when LAM is applicable.
>
>For instruction emulation, untag address in __linearize() before
>canonical check. LAM doesn't apply to instruction fetch and invlpg,
>use KVM_X86_UNTAG_ADDR_SKIP_LAM to skip LAM untag.
>
>For vmexit handlings related to 64-bit linear address:
>- Cases need to untag address
>  Operand(s) of VMX instructions and INVPCID
>  Operand(s) of SGX ENCLS
>  Linear address in INVVPID descriptor.
>- Cases LAM doesn't apply to (no change needed)
>  Operand of INVLPG
>  Linear address in INVPCID descriptor
>
>Co-developed-by: Robert Hoo <robert.hu@linux.intel.com>
>Signed-off-by: Robert Hoo <robert.hu@linux.intel.com>
>Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
>Tested-by: Xuelian Guo <xuelian.guo@intel.com>
>---
> arch/x86/kvm/emulate.c     | 23 ++++++++++++++++++-----
> arch/x86/kvm/kvm_emulate.h |  2 ++
> arch/x86/kvm/vmx/nested.c  |  4 ++++
> arch/x86/kvm/vmx/sgx.c     |  1 +
> arch/x86/kvm/x86.c         | 10 ++++++++++
> 5 files changed, 35 insertions(+), 5 deletions(-)
>
>diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
>index a20bec931764..b7df465eccf2 100644
>--- a/arch/x86/kvm/emulate.c
>+++ b/arch/x86/kvm/emulate.c
>@@ -688,7 +688,8 @@ static __always_inline int __linearize(struct x86_emulate_ctxt *ctxt,
> 				       struct segmented_address addr,
> 				       unsigned *max_size, unsigned size,
> 				       bool write, bool fetch,
>-				       enum x86emul_mode mode, ulong *linear)
>+				       enum x86emul_mode mode, ulong *linear,
>+				       u64 untag_flags)

@write and @fetch are like flags. I think we can consolidate them into
the @flags first as a cleanup patch and then add a flag for LAM.