x86/hyperv: Use TDX GHCI to access some MSRs in a TDX VM with the paravisor

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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>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230824080712.30327-9-decui@microsoft.com

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This commit is contained in:

Dexuan Cui 2023-08-24 01:07:10 -07:00 • committed by Wei Liu

parent 2337829504

commit b9b4fe3a72

4 changed files with 77 additions and 16 deletions

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8

arch/x86/hyperv/hv_init.c

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69

arch/x86/hyperv/ivm.c

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8

arch/x86/include/asm/mshyperv.h

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8

arch/x86/kernel/cpu/mshyperv.c

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