KVM: x86: Add helper to retrieve current value of user return MSR

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commit 9bc3663507 upstream.

In the user return MSR support, the cached value is always the hardware
value of the specific MSR. Therefore, add a helper to retrieve the
cached value, which can replace the need for RDMSR, for example, to
allow SEV-ES guests to restore the correct host hardware value without
using RDMSR.

Cc: stable@vger.kernel.org
Signed-off-by: Hou Wenlong <houwenlong.hwl@antgroup.com>
[sean: drop "cache" from the name, make it a one-liner, tag for stable]
Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>
Link: https://lore.kernel.org/r/20250923153738.1875174-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Hou Wenlong 2025-09-23 08:37:37 -07:00 • committed by Greg Kroah-Hartman

parent d4c322913a

commit 1406a670b3

2 changed files with 7 additions and 0 deletions

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arch/x86/include/asm/kvm_host.h

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arch/x86/kvm/x86.c

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