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 sanity checks and let userspace decide what to do. Signed-off-by: Binbin Wu <binbin.wu@xxxxxxxxxxxxxxx> --- Hypercalls exit to userspace breakout: - 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 | 8 ++++++ arch/x86/kvm/vmx/tdx.c | 50 ++++++++++++++++++++++++++++++++++ include/uapi/linux/kvm.h | 1 + 3 files changed, 59 insertions(+) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index edc070c6e19b..bb39da72c647 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -6815,6 +6815,7 @@ 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]; @@ -6841,6 +6842,13 @@ 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_TDX_FATAL -- an TDX guest requested termination. + The error codes of the guest's GHCI is stored in `data[0]`. + If the bit 63 of `data[0]` is set, it indicates there is TD specified + additional information provided in a page, which is shared memory. The + guest physical address of the information page is stored in `data[1]`. + An optional error message is provided by `data[2]` ~ `data[9]`, which is + byte sequence, LSB filled first. Typically, ASCII code(0x20-0x7e) is filled. - 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. diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 553f4cbe0693..a79f9ca962d1 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -1093,6 +1093,54 @@ static int tdx_map_gpa(struct kvm_vcpu *vcpu) return 1; } +static int tdx_report_fatal_error(struct kvm_vcpu *vcpu) +{ + u64 reg_mask = kvm_rcx_read(vcpu); + u64* opt_regs; + + /* + * Skip sanity checks and let userspace decide what to do if sanity + * checks fail. + */ + vcpu->run->exit_reason = KVM_EXIT_SYSTEM_EVENT; + vcpu->run->system_event.type = KVM_SYSTEM_EVENT_TDX_FATAL; + vcpu->run->system_event.ndata = 10; + /* Error codes. */ + vcpu->run->system_event.data[0] = tdvmcall_a0_read(vcpu); + /* GPA of additional information page. */ + vcpu->run->system_event.data[1] = tdvmcall_a1_read(vcpu); + /* Information passed via registers (up to 64 bytes). */ + opt_regs = &vcpu->run->system_event.data[2]; + +#define COPY_REG(REG, MASK) \ + do { \ + if (reg_mask & MASK) \ + *opt_regs = kvm_ ## REG ## _read(vcpu); \ + else \ + *opt_regs = 0; \ + opt_regs++; \ + } while (0) + + /* The order is defined in GHCI. */ + COPY_REG(r14, BIT_ULL(14)); + COPY_REG(r15, BIT_ULL(15)); + COPY_REG(rbx, BIT_ULL(3)); + COPY_REG(rdi, BIT_ULL(7)); + COPY_REG(rsi, BIT_ULL(6)); + COPY_REG(r8, BIT_ULL(8)); + COPY_REG(r9, BIT_ULL(9)); + COPY_REG(rdx, BIT_ULL(2)); + + /* + * Set the status code according to GHCI spec, although the vCPU may + * not return back to guest. + */ + tdvmcall_set_return_code(vcpu, TDVMCALL_STATUS_SUCCESS); + + /* Forward request to userspace. */ + return 0; +} + static int handle_tdvmcall(struct kvm_vcpu *vcpu) { if (tdvmcall_exit_type(vcpu)) @@ -1101,6 +1149,8 @@ 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 637efc055145..c173c8dfcf83 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
