On 9/8/21 12:04 PM, Paolo Bonzini wrote:
> From: Sean Christopherson <sean.j.christopher...@intel.com>
>
> Expose SGX to the guest if and only if KVM is enabled and supports
> virtualization of SGX. While the majority of ENCLS can be emulated to
> some degree, because SGX uses a hardware-based root of trust, the
> attestation aspects of SGX cannot be emulated in software, i.e.
> ultimately emulation will fail as software cannot generate a valid
> quote/report. The complexity of partially emulating SGX in Qemu far
> outweighs the value added, e.g. an SGX specific simulator for userspace
> applications can emulate SGX for development and testing purposes.
>
> Note, access to the PROVISIONKEY is not yet advertised to the guest as
> KVM blocks access to the PROVISIONKEY by default and requires userspace
> to provide additional credentials (via ioctl()) to expose PROVISIONKEY.
>
> Signed-off-by: Sean Christopherson <sean.j.christopher...@intel.com>
> Signed-off-by: Yang Zhong <yang.zh...@intel.com>
'---' separator goes here.
>
> v3-->v4:
> - Replaced g_malloc0() with directly ....
> Message-Id: <20210719112136.57018-13-yang.zh...@intel.com>
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
> ---
> hw/i386/sgx.c | 17 +++++++++
> include/hw/i386/sgx-epc.h | 2 +
> target/i386/cpu.c | 77 +++++++++++++++++++++++++++++++++++++++
> 3 files changed, 96 insertions(+)
>
> diff --git a/hw/i386/sgx.c b/hw/i386/sgx.c
> index e77deb0b00..5f988c6368 100644
> --- a/hw/i386/sgx.c
> +++ b/hw/i386/sgx.c
> @@ -18,6 +18,23 @@
> #include "qapi/error.h"
> #include "exec/address-spaces.h"
>
> +int sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
> +{
> + PCMachineState *pcms = PC_MACHINE(qdev_get_machine());
> + SGXEPCDevice *epc;
> +
> + if (pcms->sgx_epc.size == 0 || pcms->sgx_epc.nr_sections <= section_nr) {
> + return 1;
> + }
> +
> + epc = pcms->sgx_epc.sections[section_nr];
> +
> + *addr = epc->addr;
> + *size = memory_device_get_region_size(MEMORY_DEVICE(epc), &error_fatal);
> +
> + return 0;
Undocumented, but IIUC this return a boolean.
> +}
> +
> static int sgx_epc_set_property(void *opaque, const char *name,
> const char *value, Error **errp)
> {
> diff --git a/include/hw/i386/sgx-epc.h b/include/hw/i386/sgx-epc.h
> index 2b2490892b..f85fd2a4ca 100644
> --- a/include/hw/i386/sgx-epc.h
> +++ b/include/hw/i386/sgx-epc.h
> @@ -55,4 +55,6 @@ typedef struct SGXEPCState {
> int nr_sections;
> } SGXEPCState;
>
> +int sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size);
bool.
> +
> #endif
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index 59cb2c2d03..38cf507199 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -36,6 +36,7 @@
> #ifndef CONFIG_USER_ONLY
> #include "exec/address-spaces.h"
> #include "hw/boards.h"
> +#include "hw/i386/sgx-epc.h"
> #endif
>
> #include "disas/capstone.h"
> @@ -5334,6 +5335,25 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> uint32_t count,
> *ecx |= CPUID_7_0_ECX_OSPKE;
> }
> *edx = env->features[FEAT_7_0_EDX]; /* Feature flags */
> +
> + /*
> + * SGX cannot be emulated in software. If hardware does not
> + * support enabling SGX and/or SGX flexible launch control,
> + * then we need to update the VM's CPUID values accordingly.
> + */
> + if ((*ebx & CPUID_7_0_EBX_SGX) &&
> + (!kvm_enabled() ||
> + !(kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7, 0,
> R_EBX) &
> + CPUID_7_0_EBX_SGX))) {
> + *ebx &= ~CPUID_7_0_EBX_SGX;
> + }
> +
> + if ((*ecx & CPUID_7_0_ECX_SGX_LC) &&
> + (!(*ebx & CPUID_7_0_EBX_SGX) || !kvm_enabled() ||
> + !(kvm_arch_get_supported_cpuid(cs->kvm_state, 0x7, 0,
> R_ECX) &
> + CPUID_7_0_ECX_SGX_LC))) {
> + *ecx &= ~CPUID_7_0_ECX_SGX_LC;
> + }
> } else if (count == 1) {
> *eax = env->features[FEAT_7_1_EAX];
> *ebx = 0;
> @@ -5469,6 +5489,63 @@ void cpu_x86_cpuid(CPUX86State *env, uint32_t index,
> uint32_t count,
> }
> break;
> }
> + case 0x12:
> +#ifndef CONFIG_USER_ONLY
> + if (!kvm_enabled() ||
> + !(env->features[FEAT_7_0_EBX] & CPUID_7_0_EBX_SGX)) {
> + *eax = *ebx = *ecx = *edx = 0;
> + break;
> + }
> +
> + /*
> + * SGX sub-leafs CPUID.0x12.{0x2..N} enumerate EPC sections.
> Retrieve
> + * the EPC properties, e.g. confidentiality and integrity, from the
> + * host's first EPC section, i.e. assume there is one EPC section or
> + * that all EPC sections have the same security properties.
> + */
> + if (count > 1) {
> + uint64_t epc_addr, epc_size;
> +
> + if (sgx_epc_get_section(count - 2, &epc_addr, &epc_size)) {
Missing stub for when CONFIG_SGX=n:
bool sgx_epc_get_section(int section_nr, uint64_t *addr, uint64_t *size)
{
g_assert_not_reached();
}
