| Message ID | 20241201035358.2193078-4-binbin.wu@linux.intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | KVM: TDX: TDX hypercalls may exit to userspace | expand |
On Sun, Dec 01, 2024 at 11:53:52AM +0800, Binbin Wu wrote: >From: Isaku Yamahata <isaku.yamahata@intel.com> > >Handle KVM hypercall for TDX according to TDX Guest-Host Communication >Interface (GHCI) specification. > >The TDX GHCI specification defines the ABI for the guest TD to issue >hypercalls. When R10 is non-zero, it indicates the TDG.VP.VMCALL is >vendor-specific. KVM uses R10 as KVM hypercall number and R11-R14 >as 4 arguments, while the error code is returned in R10. Follow the >ABI and handle the KVM hypercall for TDX. > >Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >Co-developed-by: Binbin Wu <binbin.wu@linux.intel.com> >Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com> >--- >Hypercalls exit to userspace breakout: >- Renamed from "KVM: TDX: handle KVM hypercall with TDG.VP.VMCALL" to > "KVM: TDX: Handle KVM hypercall with TDG.VP.VMCALL". >- Update the change log. >- Rebased on Sean's "Prep KVM hypercall handling for TDX" patch set. > https://lore.kernel.org/kvm/20241128004344.4072099-1-seanjc@google.com >- Use the right register (i.e. R10) to set the return code after returning > back from userspace. >--- > arch/x86/kvm/vmx/tdx.c | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) > >diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c >index 19fd8a5dabd0..4cc55b120ab0 100644 >--- a/arch/x86/kvm/vmx/tdx.c >+++ b/arch/x86/kvm/vmx/tdx.c >@@ -957,8 +957,39 @@ static int tdx_handle_triple_fault(struct kvm_vcpu *vcpu) > return 0; > } > >+ >+static int complete_hypercall_exit(struct kvm_vcpu *vcpu) >+{ >+ kvm_r10_write(vcpu, vcpu->run->hypercall.ret); Use tdvmcall_set_return_code() here? it would be more self-explanatory. >+ return 1; >+} >+ >+static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu) >+{ >+ int r; >+ >+ /* >+ * ABI for KVM tdvmcall argument: >+ * In Guest-Hypervisor Communication Interface(GHCI) specification, >+ * Non-zero leaf number (R10 != 0) is defined to indicate >+ * vendor-specific. KVM uses this for KVM hypercall. NOTE: KVM >+ * hypercall number starts from one. Zero isn't used for KVM hypercall >+ * number. >+ * >+ * R10: KVM hypercall number >+ * arguments: R11, R12, R13, R14. >+ */ >+ r = __kvm_emulate_hypercall(vcpu, r10, r11, r12, r13, r14, true, 0, note r10-14 are not declared in this function. >+ complete_hypercall_exit); >+ >+ return r > 0; >+} >+ > static int handle_tdvmcall(struct kvm_vcpu *vcpu) > { >+ if (tdvmcall_exit_type(vcpu)) >+ return tdx_emulate_vmcall(vcpu); >+ > switch (tdvmcall_leaf(vcpu)) { > default: > break; >-- >2.46.0 >
On 12/9/2024 10:58 AM, Chao Gao wrote: > On Sun, Dec 01, 2024 at 11:53:52AM +0800, Binbin Wu wrote: >> From: Isaku Yamahata <isaku.yamahata@intel.com> >> >> Handle KVM hypercall for TDX according to TDX Guest-Host Communication >> Interface (GHCI) specification. >> >> The TDX GHCI specification defines the ABI for the guest TD to issue >> hypercalls. When R10 is non-zero, it indicates the TDG.VP.VMCALL is >> vendor-specific. KVM uses R10 as KVM hypercall number and R11-R14 >> as 4 arguments, while the error code is returned in R10. Follow the >> ABI and handle the KVM hypercall for TDX. >> >> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com> >> Co-developed-by: Binbin Wu <binbin.wu@linux.intel.com> >> Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com> >> --- >> Hypercalls exit to userspace breakout: >> - Renamed from "KVM: TDX: handle KVM hypercall with TDG.VP.VMCALL" to >> "KVM: TDX: Handle KVM hypercall with TDG.VP.VMCALL". >> - Update the change log. >> - Rebased on Sean's "Prep KVM hypercall handling for TDX" patch set. >> https://lore.kernel.org/kvm/20241128004344.4072099-1-seanjc@google.com >> - Use the right register (i.e. R10) to set the return code after returning >> back from userspace. >> --- >> arch/x86/kvm/vmx/tdx.c | 31 +++++++++++++++++++++++++++++++ >> 1 file changed, 31 insertions(+) >> >> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c >> index 19fd8a5dabd0..4cc55b120ab0 100644 >> --- a/arch/x86/kvm/vmx/tdx.c >> +++ b/arch/x86/kvm/vmx/tdx.c >> @@ -957,8 +957,39 @@ static int tdx_handle_triple_fault(struct kvm_vcpu *vcpu) >> return 0; >> } >> >> + >> +static int complete_hypercall_exit(struct kvm_vcpu *vcpu) >> +{ >> + kvm_r10_write(vcpu, vcpu->run->hypercall.ret); > Use tdvmcall_set_return_code() here? it would be more self-explanatory. Yes, it's better. Thanks! > >> + return 1; >> +} >> + >> +static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu) >> +{ >> + int r; >> + >> + /* >> + * ABI for KVM tdvmcall argument: >> + * In Guest-Hypervisor Communication Interface(GHCI) specification, >> + * Non-zero leaf number (R10 != 0) is defined to indicate >> + * vendor-specific. KVM uses this for KVM hypercall. NOTE: KVM >> + * hypercall number starts from one. Zero isn't used for KVM hypercall >> + * number. >> + * >> + * R10: KVM hypercall number >> + * arguments: R11, R12, R13, R14. >> + */ >> + r = __kvm_emulate_hypercall(vcpu, r10, r11, r12, r13, r14, true, 0, > note r10-14 are not declared in this function. __kvm_emulate_hypercall() is a macro, so these will be replaced by kvm_{r10, r11, r12, r13, r14}_read(). > >> + complete_hypercall_exit); >> + >> + return r > 0; >> +} >> + >> static int handle_tdvmcall(struct kvm_vcpu *vcpu) >> { >> + if (tdvmcall_exit_type(vcpu)) >> + return tdx_emulate_vmcall(vcpu); >> + >> switch (tdvmcall_leaf(vcpu)) { >> default: >> break; >> -- >> 2.46.0 >>
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c index 19fd8a5dabd0..4cc55b120ab0 100644 --- a/arch/x86/kvm/vmx/tdx.c +++ b/arch/x86/kvm/vmx/tdx.c @@ -957,8 +957,39 @@ static int tdx_handle_triple_fault(struct kvm_vcpu *vcpu) return 0; } + +static int complete_hypercall_exit(struct kvm_vcpu *vcpu) +{ + kvm_r10_write(vcpu, vcpu->run->hypercall.ret); + return 1; +} + +static int tdx_emulate_vmcall(struct kvm_vcpu *vcpu) +{ + int r; + + /* + * ABI for KVM tdvmcall argument: + * In Guest-Hypervisor Communication Interface(GHCI) specification, + * Non-zero leaf number (R10 != 0) is defined to indicate + * vendor-specific. KVM uses this for KVM hypercall. NOTE: KVM + * hypercall number starts from one. Zero isn't used for KVM hypercall + * number. + * + * R10: KVM hypercall number + * arguments: R11, R12, R13, R14. + */ + r = __kvm_emulate_hypercall(vcpu, r10, r11, r12, r13, r14, true, 0, + complete_hypercall_exit); + + return r > 0; +} + static int handle_tdvmcall(struct kvm_vcpu *vcpu) { + if (tdvmcall_exit_type(vcpu)) + return tdx_emulate_vmcall(vcpu); + switch (tdvmcall_leaf(vcpu)) { default: break;