Convert TDG.VP.VMCALL<ReportFatalError> to KVM_EXIT_SYSTEM_EVENT with a new type KVM_SYSTEM_EVENT_TDX_FATAL and forward it to userspace for handling. TD guest can use TDG.VP.VMCALL<ReportFatalError> to report the fatal error it has experienced. This hypercall is special because TD guest is requesting a termination with the error information, KVM needs to forward the hypercall to userspace anyway, KVM doesn't do parsing or conversion, it just dumps the 16 general-purpose registers to userspace and let userspace decide what to do. Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> --- Hypercalls exit to userspace v3: - Dump all 16 general-purpose registers to userspace. (Sean) Hypercalls exit to userspace v2: - Use vp_enter_args instead of x86 registers. - vcpu->run->system_event.ndata is not hardcoded to 10. (Xiaoyao) - Undefine COPY_REG after use. (Yilun) - Updated the document about KVM_SYSTEM_EVENT_TDX_FATAL. (Chao) Hypercalls exit to userspace v1: - New added. Implement one of the hypercalls need to exit to userspace for handling after reverting "KVM: TDX: Add KVM Exit for TDX TDG.VP.VMCALL", which tries to resolve Sean's comment. https://lore.kernel.org/kvm/Zg18ul8Q4PGQMWam@xxxxxxxxxx/ - Use TDVMCALL_STATUS prefix for TDX call status codes (Binbin) --- Documentation/virt/kvm/api.rst | 9 ++++++--- arch/x86/kvm/vmx/tdx.c | 28 ++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 3 files changed, 35 insertions(+), 3 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 2b52eb77e29c..2d75edc9db4f 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6823,6 +6823,7 @@ should put the acknowledged interrupt vector into the 'epr' field. #define KVM_SYSTEM_EVENT_WAKEUP 4 #define KVM_SYSTEM_EVENT_SUSPEND 5 #define KVM_SYSTEM_EVENT_SEV_TERM 6 + #define KVM_SYSTEM_EVENT_TDX_FATAL 7 __u32 type; __u32 ndata; __u64 data[16]; @@ -6849,9 +6850,11 @@ Valid values for 'type' are: reset/shutdown of the VM. - KVM_SYSTEM_EVENT_SEV_TERM -- an AMD SEV guest requested termination. The guest physical address of the guest's GHCB is stored in `data[0]`. - - KVM_SYSTEM_EVENT_WAKEUP -- the exiting vCPU is in a suspended state and - KVM has recognized a wakeup event. Userspace may honor this event by - marking the exiting vCPU as runnable, or deny it and call KVM_RUN again. + - KVM_SYSTEM_EVENT_TDX_FATAL -- a TDX guest reported a fatal error state. + KVM doesn't do any parsing or conversion, it just dumps 16 general-purpose + registers to userspace, in ascending order of the 4-bit indices for x86-64 + general-purpose registers in instruction encoding, as defined in the Intel + SDM. - KVM_SYSTEM_EVENT_SUSPEND -- the guest has requested a suspension of the VM. diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 7b2f4c32f01b..7c8356299a25 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1093,11 +1093,39 @@ static int tdx_map_gpa(struct kvm_vcpu *vcpu) return 1; } +static int tdx_report_fatal_error(struct kvm_vcpu *vcpu) +{ + struct vcpu_tdx *tdx = to_tdx(vcpu); + u64 *regs = vcpu->run->system_event.data; + u64 *module_regs = &tdx->vp_enter_args.r8; + int index = VCPU_REGS_RAX; + + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; + vcpu->run->system_event.type = KVM_SYSTEM_EVENT_TDX_FATAL; + vcpu->run->system_event.ndata = 16; + + /* Dump 16 general-purpose registers to userspace in ascending order. */ + regs[index++] = tdx->vp_enter_ret; + regs[index++] = tdx->vp_enter_args.rcx; + regs[index++] = tdx->vp_enter_args.rdx; + regs[index++] = tdx->vp_enter_args.rbx; + regs[index++] = 0; + regs[index++] = 0; + regs[index++] = tdx->vp_enter_args.rsi; + regs[index] = tdx->vp_enter_args.rdi; + for (index = 0; index < 8; index++) + regs[VCPU_REGS_R8 + index] = module_regs[index]; + + return 0; +} + static int handle_tdvmcall(struct kvm_vcpu *vcpu) { switch (tdvmcall_leaf(vcpu)) { case TDVMCALL_MAP_GPA: return tdx_map_gpa(vcpu); + case TDVMCALL_REPORT_FATAL_ERROR: + return tdx_report_fatal_error(vcpu); default: break; } diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h index 45e6d8fca9b9..937400350317 100644 --- a/include/uapi/linux/kvm.h +++ b/include/uapi/linux/kvm.h @@ -375,6 +375,7 @@ struct kvm_run { #define KVM_SYSTEM_EVENT_WAKEUP 4 #define KVM_SYSTEM_EVENT_SUSPEND 5 #define KVM_SYSTEM_EVENT_SEV_TERM 6 +#define KVM_SYSTEM_EVENT_TDX_FATAL 7 __u32 type; __u32 ndata; union { -- 2.46.0
