Re: [PATCH v3 08/10] x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor

Tianyu Lan
2023-08-24T14:45:30Z

On 8/24/2023 4:07 PM, Dexuan Cui wrote:
> When the paravisor is present, a SNP VM must use GHCB to access some
> special MSRs, including HV_X64_MSR_GUEST_OS_ID and some SynIC MSRs.
>
> Similarly, when the paravisor is present, a TDX VM must use TDX GHCI
> to access the same MSRs.
>
> Implement hv_tdx_msr_write() and hv_tdx_msr_read(), and use the helper
> functions hv_ivm_msr_read() and hv_ivm_msr_write() to access the MSRs
> in a unified way for SNP/TDX VMs with the paravisor.
>
> Do not export hv_tdx_msr_write() and hv_tdx_msr_read(), because we never
> really used hv_ghcb_msr_write() and hv_ghcb_msr_read() in any module.
>
> Update arch/x86/include/asm/mshyperv.h so that the kernel can still build
> if CONFIG_AMD_MEM_ENCRYPT or CONFIG_INTEL_TDX_GUEST is not set, or
> neither is set.
>
> Signed-off-by: Dexuan Cui <decui@microsoft.com>

Reviewed-by: Tianyu Lan <tiala@microsoft.com>