| Message ID | 20241105062408.3533704-6-xiaoyao.li@intel.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | QEMU TDX support | expand |
On Tue, Nov 05, 2024 at 01:23:13AM -0500, Xiaoyao Li wrote: > KVM provides TDX capabilities via sub command KVM_TDX_CAPABILITIES of > IOCTL(KVM_MEMORY_ENCRYPT_OP). Get the capabilities when initializing > TDX context. It will be used to validate user's setting later. > > Since there is no interface reporting how many cpuid configs contains in > KVM_TDX_CAPABILITIES, QEMU chooses to try starting with a known number > and abort when it exceeds KVM_MAX_CPUID_ENTRIES. > > Besides, introduce the interfaces to invoke TDX "ioctls" at VCPU scope > in preparation. > > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > --- > Changes in v6: > - Pass CPUState * to tdx_vcpu_ioctl(); > - update commit message to remove platform scope thing; > - dump hw_error when it's non-zero to help debug; > > Changes in v4: > - use {} to initialize struct kvm_tdx_cmd, to avoid memset(); > - remove tdx_platform_ioctl() because no user; > > Changes in v3: > - rename __tdx_ioctl() to tdx_ioctl_internal() > - Pass errp in get_tdx_capabilities(); > > changes in v2: > - Make the error message more clear; > > changes in v1: > - start from nr_cpuid_configs = 6 for the loop; > - stop the loop when nr_cpuid_configs exceeds KVM_MAX_CPUID_ENTRIES; > --- > target/i386/kvm/kvm.c | 2 - > target/i386/kvm/kvm_i386.h | 2 + > target/i386/kvm/tdx.c | 93 +++++++++++++++++++++++++++++++++++++- > 3 files changed, 94 insertions(+), 3 deletions(-) > > diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > index 2bbac603da70..b843de7f2379 100644 > --- a/target/i386/kvm/kvm.c > +++ b/target/i386/kvm/kvm.c > @@ -1782,8 +1782,6 @@ static int hyperv_init_vcpu(X86CPU *cpu) > > static Error *invtsc_mig_blocker; > > -#define KVM_MAX_CPUID_ENTRIES 100 > - > static void kvm_init_xsave(CPUX86State *env) > { > if (has_xsave2) { > diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h > index 9de9c0d30388..7ac4c3a91171 100644 > --- a/target/i386/kvm/kvm_i386.h > +++ b/target/i386/kvm/kvm_i386.h > @@ -13,6 +13,8 @@ > > #include "sysemu/kvm.h" > > +#define KVM_MAX_CPUID_ENTRIES 100 > + > #ifdef CONFIG_KVM > > #define kvm_pit_in_kernel() \ > diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c > index 85f006c1d6b4..907044910fec 100644 > --- a/target/i386/kvm/tdx.c > +++ b/target/i386/kvm/tdx.c > @@ -12,17 +12,108 @@ > */ > > #include "qemu/osdep.h" > +#include "qemu/error-report.h" > +#include "qapi/error.h" > #include "qom/object_interfaces.h" > > #include "hw/i386/x86.h" > #include "kvm_i386.h" > #include "tdx.h" > > +static struct kvm_tdx_capabilities *tdx_caps; > + > +enum tdx_ioctl_level { > + TDX_VM_IOCTL, > + TDX_VCPU_IOCTL, > +}; > + > +static int tdx_ioctl_internal(enum tdx_ioctl_level level, void *state, > + int cmd_id, __u32 flags, void *data) > +{ > + struct kvm_tdx_cmd tdx_cmd = {}; > + int r; > + > + tdx_cmd.id = cmd_id; > + tdx_cmd.flags = flags; > + tdx_cmd.data = (__u64)(unsigned long)data; > + > + switch (level) { > + case TDX_VM_IOCTL: > + r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd); > + break; > + case TDX_VCPU_IOCTL: > + r = kvm_vcpu_ioctl(state, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd); > + break; > + default: > + error_report("Invalid tdx_ioctl_level %d", level); > + exit(1); > + } > + > + if (r && tdx_cmd.hw_error) { > + error_report("TDX ioctl %d return with %d, hw_errors: 0x%llx", > + cmd_id, r, tdx_cmd.hw_error); > + } > + return r; > +} I feel like the error handling of this method is rather inconsistent. In one place we error_report() and then exit(), in another place we error_report() but return, and in another place we report nothing at all. When we return, the caller propagates an Error **errp object, but this propagated message lacks the potentially useful 'hw_errors' info. IMHO this method ought to have an 'Error **errp' parameter and always fill it & propagate. Let the caller decide whether to exit or not. If you continue returning 'r', then the caller can still handle E2BIG, discarding the 'Error' object in that case. > + > +static inline int tdx_vm_ioctl(int cmd_id, __u32 flags, void *data) > +{ > + return tdx_ioctl_internal(TDX_VM_IOCTL, NULL, cmd_id, flags, data); > +} > + > +static inline int tdx_vcpu_ioctl(CPUState *cpu, int cmd_id, __u32 flags, > + void *data) > +{ > + return tdx_ioctl_internal(TDX_VCPU_IOCTL, cpu, cmd_id, flags, data); > +} > + > +static int get_tdx_capabilities(Error **errp) > +{ > + struct kvm_tdx_capabilities *caps; > + /* 1st generation of TDX reports 6 cpuid configs */ > + int nr_cpuid_configs = 6; > + size_t size; > + int r; > + > + do { > + size = sizeof(struct kvm_tdx_capabilities) + > + nr_cpuid_configs * sizeof(struct kvm_cpuid_entry2); > + caps = g_malloc0(size); > + caps->cpuid.nent = nr_cpuid_configs; > + > + r = tdx_vm_ioctl(KVM_TDX_CAPABILITIES, 0, caps); > + if (r == -E2BIG) { > + g_free(caps); > + nr_cpuid_configs *= 2; > + if (nr_cpuid_configs > KVM_MAX_CPUID_ENTRIES) { > + error_setg(errp, "%s: KVM TDX seems broken that number of CPUID" > + " entries in kvm_tdx_capabilities exceeds limit %d", > + __func__, KVM_MAX_CPUID_ENTRIES); > + return r; > + } > + } else if (r < 0) { > + g_free(caps); > + error_setg_errno(errp, -r, "%s: KVM_TDX_CAPABILITIES failed", __func__); > + return r; > + } > + } while (r == -E2BIG); > + > + tdx_caps = caps; > + > + return 0; > +} > + > static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) > { > + int r = 0; > + > kvm_mark_guest_state_protected(); > > - return 0; > + if (!tdx_caps) { > + r = get_tdx_capabilities(errp); > + } > + > + return r; > } > > static int tdx_kvm_type(X86ConfidentialGuest *cg) > -- > 2.34.1 > With regards, Daniel
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c index 2bbac603da70..b843de7f2379 100644 --- a/target/i386/kvm/kvm.c +++ b/target/i386/kvm/kvm.c @@ -1782,8 +1782,6 @@ static int hyperv_init_vcpu(X86CPU *cpu) static Error *invtsc_mig_blocker; -#define KVM_MAX_CPUID_ENTRIES 100 - static void kvm_init_xsave(CPUX86State *env) { if (has_xsave2) { diff --git a/target/i386/kvm/kvm_i386.h b/target/i386/kvm/kvm_i386.h index 9de9c0d30388..7ac4c3a91171 100644 --- a/target/i386/kvm/kvm_i386.h +++ b/target/i386/kvm/kvm_i386.h @@ -13,6 +13,8 @@ #include "sysemu/kvm.h" +#define KVM_MAX_CPUID_ENTRIES 100 + #ifdef CONFIG_KVM #define kvm_pit_in_kernel() \ diff --git a/target/i386/kvm/tdx.c b/target/i386/kvm/tdx.c index 85f006c1d6b4..907044910fec 100644 --- a/target/i386/kvm/tdx.c +++ b/target/i386/kvm/tdx.c @@ -12,17 +12,108 @@ */ #include "qemu/osdep.h" +#include "qemu/error-report.h" +#include "qapi/error.h" #include "qom/object_interfaces.h" #include "hw/i386/x86.h" #include "kvm_i386.h" #include "tdx.h" +static struct kvm_tdx_capabilities *tdx_caps; + +enum tdx_ioctl_level { + TDX_VM_IOCTL, + TDX_VCPU_IOCTL, +}; + +static int tdx_ioctl_internal(enum tdx_ioctl_level level, void *state, + int cmd_id, __u32 flags, void *data) +{ + struct kvm_tdx_cmd tdx_cmd = {}; + int r; + + tdx_cmd.id = cmd_id; + tdx_cmd.flags = flags; + tdx_cmd.data = (__u64)(unsigned long)data; + + switch (level) { + case TDX_VM_IOCTL: + r = kvm_vm_ioctl(kvm_state, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd); + break; + case TDX_VCPU_IOCTL: + r = kvm_vcpu_ioctl(state, KVM_MEMORY_ENCRYPT_OP, &tdx_cmd); + break; + default: + error_report("Invalid tdx_ioctl_level %d", level); + exit(1); + } + + if (r && tdx_cmd.hw_error) { + error_report("TDX ioctl %d return with %d, hw_errors: 0x%llx", + cmd_id, r, tdx_cmd.hw_error); + } + return r; +} + +static inline int tdx_vm_ioctl(int cmd_id, __u32 flags, void *data) +{ + return tdx_ioctl_internal(TDX_VM_IOCTL, NULL, cmd_id, flags, data); +} + +static inline int tdx_vcpu_ioctl(CPUState *cpu, int cmd_id, __u32 flags, + void *data) +{ + return tdx_ioctl_internal(TDX_VCPU_IOCTL, cpu, cmd_id, flags, data); +} + +static int get_tdx_capabilities(Error **errp) +{ + struct kvm_tdx_capabilities *caps; + /* 1st generation of TDX reports 6 cpuid configs */ + int nr_cpuid_configs = 6; + size_t size; + int r; + + do { + size = sizeof(struct kvm_tdx_capabilities) + + nr_cpuid_configs * sizeof(struct kvm_cpuid_entry2); + caps = g_malloc0(size); + caps->cpuid.nent = nr_cpuid_configs; + + r = tdx_vm_ioctl(KVM_TDX_CAPABILITIES, 0, caps); + if (r == -E2BIG) { + g_free(caps); + nr_cpuid_configs *= 2; + if (nr_cpuid_configs > KVM_MAX_CPUID_ENTRIES) { + error_setg(errp, "%s: KVM TDX seems broken that number of CPUID" + " entries in kvm_tdx_capabilities exceeds limit %d", + __func__, KVM_MAX_CPUID_ENTRIES); + return r; + } + } else if (r < 0) { + g_free(caps); + error_setg_errno(errp, -r, "%s: KVM_TDX_CAPABILITIES failed", __func__); + return r; + } + } while (r == -E2BIG); + + tdx_caps = caps; + + return 0; +} + static int tdx_kvm_init(ConfidentialGuestSupport *cgs, Error **errp) { + int r = 0; + kvm_mark_guest_state_protected(); - return 0; + if (!tdx_caps) { + r = get_tdx_capabilities(errp); + } + + return r; } static int tdx_kvm_type(X86ConfidentialGuest *cg)
KVM provides TDX capabilities via sub command KVM_TDX_CAPABILITIES of IOCTL(KVM_MEMORY_ENCRYPT_OP). Get the capabilities when initializing TDX context. It will be used to validate user's setting later. Since there is no interface reporting how many cpuid configs contains in KVM_TDX_CAPABILITIES, QEMU chooses to try starting with a known number and abort when it exceeds KVM_MAX_CPUID_ENTRIES. Besides, introduce the interfaces to invoke TDX "ioctls" at VCPU scope in preparation. Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> --- Changes in v6: - Pass CPUState * to tdx_vcpu_ioctl(); - update commit message to remove platform scope thing; - dump hw_error when it's non-zero to help debug; Changes in v4: - use {} to initialize struct kvm_tdx_cmd, to avoid memset(); - remove tdx_platform_ioctl() because no user; Changes in v3: - rename __tdx_ioctl() to tdx_ioctl_internal() - Pass errp in get_tdx_capabilities(); changes in v2: - Make the error message more clear; changes in v1: - start from nr_cpuid_configs = 6 for the loop; - stop the loop when nr_cpuid_configs exceeds KVM_MAX_CPUID_ENTRIES; --- target/i386/kvm/kvm.c | 2 - target/i386/kvm/kvm_i386.h | 2 + target/i386/kvm/tdx.c | 93 +++++++++++++++++++++++++++++++++++++- 3 files changed, 94 insertions(+), 3 deletions(-)