From: Erdem Aktas <[email protected]> TDX VMs need to notify the host, e.g. ucall. Add tdvmcall() to allow VMs to issue TDG.VP.VMCALL with a single function call instead of open-coding TDVMCALL registers setup at every call site.
The helper makes standard GHCI TDVMCALLs: the caller passes the GHCI sub-function and up to four arguments and returns the TDVMCALL status from R10. Co-developed-by: Sagi Shahar <[email protected]> Signed-off-by: Sagi Shahar <[email protected]> Co-developed-by: Lisa Wang <[email protected]> Signed-off-by: Lisa Wang <[email protected]> Signed-off-by: Erdem Aktas <[email protected]> Reviewed-by: Ackerley Tng <[email protected]> --- tools/testing/selftests/kvm/Makefile.kvm | 1 + tools/testing/selftests/kvm/include/x86/tdx/tdx.h | 9 ++++++ tools/testing/selftests/kvm/lib/x86/tdx/tdx.S | 39 +++++++++++++++++++++++ 3 files changed, 49 insertions(+) diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index 9464168e361a..495de8ef8166 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -34,6 +34,7 @@ LIBKVM_x86 += lib/x86/tdx/tdx_util.c LIBKVM_x86 += lib/x86/ucall.c LIBKVM_x86 += lib/x86/vmx.c LIBKVM_x86 += lib/x86/tdx/td_boot.S +LIBKVM_x86 += lib/x86/tdx/tdx.S LIBKVM_arm64 += lib/arm64/gic.c LIBKVM_arm64 += lib/arm64/gic_v3.c diff --git a/tools/testing/selftests/kvm/include/x86/tdx/tdx.h b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h new file mode 100644 index 000000000000..d41a1efc8a63 --- /dev/null +++ b/tools/testing/selftests/kvm/include/x86/tdx/tdx.h @@ -0,0 +1,9 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef SELFTEST_KVM_TDX_TDX_H +#define SELFTEST_KVM_TDX_TDX_H + +#include <linux/types.h> + +u64 __tdvmcall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15); + +#endif /* SELFTEST_KVM_TDX_TDX_H */ diff --git a/tools/testing/selftests/kvm/lib/x86/tdx/tdx.S b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.S new file mode 100644 index 000000000000..e3f0f7f2232b --- /dev/null +++ b/tools/testing/selftests/kvm/lib/x86/tdx/tdx.S @@ -0,0 +1,39 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +.globl __tdvmcall +/* + * u64 __tdvmcall(u64 fn, u64 r12, u64 r13, u64 r14, u64 r15) + */ +__tdvmcall: + push %r12 + push %r13 + push %r14 + push %r15 + + /* + * Map C ABI fast arguments to TDX GHCI payload registers + * RDI=fn, RSI=r12, RDX=r13, RCX=r14, R8=r15 + */ + mov %rdi, %r11 + mov %rsi, %r12 + mov %rdx, %r13 + mov %rcx, %r14 + mov %r8, %r15 + + mov $0, %rax /* TDCALL leaf 0: TDG.VP.VMCALL */ + mov $0xFC00, %rcx /* Expose R10-R15 */ + mov $0, %r10 /* Standard GHCI call */ + + /* TDCALL instruction */ + .byte 0x66, 0x0f, 0x01, 0xcc + + /* Extract status */ + mov %r10, %rax + + pop %r15 + pop %r14 + pop %r13 + pop %r12 + ret + +.section .note.GNU-stack,"",%progbits -- 2.56.0.rc1.315.gc6ed9934b7-goog
