[PATCH v4 0/6] KVM: x86: Prep KVM hypercall handling for TDX

Sean Christopherson
2024-11-28T00:43:47Z

Effectively v4 of Binbin's series to handle hypercall exits to userspace in
a generic manner, so that TDX

Binbin and Kai, this is fairly different that what we last discussed. While
sorting through Binbin's latest patch, I stumbled on what I think/hope is an
approach that will make life easier for TDX. Rather than have common code
set the return value, _and_ have TDX implement a callback to do the same for
user return MSRs, just use the callback for all paths.

As for abusing vcpu->run->hypercall.ret... It's obviously a bit gross, but
I think it's a lesser evil than having multiple a one-line wrappers just to
trampoline in the return code.

v4:
- Fix an SEV-* bug where KVM trips the WARN in is_64_bit_mode().
- Add a pile of reworks to (hopefully) avoid as much duplicate code when
TDX comes along.

v3: https://lore.kernel.org/all/20240826022255.361406-1-binbin.wu@linux.intel.com

Binbin Wu (1):
KVM: x86: Add a helper to check for user interception of KVM
hypercalls

Sean Christopherson (5):
KVM: x86: Play nice with protected guests in complete_hypercall_exit()
KVM: x86: Move "emulate hypercall" function declarations to x86.h
KVM: x86: Bump hypercall stat prior to fully completing hypercall
KVM: x86: Always complete hypercall via function callback
KVM: x86: Refactor __kvm_emulate_hypercall() into a macro

arch/x86/include/asm/kvm_host.h | 6 ----
arch/x86/kvm/svm/sev.c | 4 +--
arch/x86/kvm/x86.c | 50 +++++++++++----------------------
arch/x86/kvm/x86.h | 28 ++++++++++++++++++
4 files changed, 47 insertions(+), 41 deletions(-)

base-commit: 4d911c7abee56771b0219a9fbf0120d06bdc9c14
--
2.47.0.338.g60cca15819-goog