> From: Zeng, Guang <guang.z...@intel.com> > Sent: Monday, January 10, 2022 5:47 PM > > On 1/10/2022 4:40 PM, Tian, Kevin wrote: > >> From: Zhong, Yang <yang.zh...@intel.com> > >> Sent: Friday, January 7, 2022 5:32 PM > >> > >> From: Jing Liu <jing2....@intel.com> > >> > >> Extended feature has large state while current > >> kvm_xsave only allows 4KB. Use new XSAVE ioctls > >> if the xstate size is large than kvm_xsave. > > shouldn't we always use the new xsave ioctls as long as > > CAP_XSAVE2 is available? > > > CAP_XSAVE2 may return legacy xsave size or 0 working with old kvm > version in which it's not available. > QEMU just use the new xsave ioctls only when the return value of > CAP_XSAVE2 is larger than legacy xsave size.
CAP_XSAVE2 is the superset of CAP_XSAVE. If available it can support both legacy 4K size or bigger. > > >> Signed-off-by: Jing Liu <jing2....@intel.com> > >> Signed-off-by: Zeng Guang <guang.z...@intel.com> > >> Signed-off-by: Wei Wang <wei.w.w...@intel.com> > >> Signed-off-by: Yang Zhong <yang.zh...@intel.com> > >> --- > >> linux-headers/asm-x86/kvm.h | 14 ++++++++++++++ > >> linux-headers/linux/kvm.h | 2 ++ > >> target/i386/cpu.h | 5 +++++ > >> target/i386/kvm/kvm.c | 16 ++++++++++++++-- > >> target/i386/xsave_helper.c | 35 > +++++++++++++++++++++++++++++++++++ > >> 5 files changed, 70 insertions(+), 2 deletions(-) > >> > >> diff --git a/linux-headers/asm-x86/kvm.h b/linux-headers/asm-x86/kvm.h > >> index 5a776a08f7..32f2a921e8 100644 > >> --- a/linux-headers/asm-x86/kvm.h > >> +++ b/linux-headers/asm-x86/kvm.h > >> @@ -376,6 +376,20 @@ struct kvm_debugregs { > >> /* for KVM_CAP_XSAVE */ > >> struct kvm_xsave { > >> __u32 region[1024]; > >> + /* > >> + * KVM_GET_XSAVE2 and KVM_SET_XSAVE write and read as many > >> bytes > >> + * as are returned by KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) > >> + * respectively, when invoked on the vm file descriptor. > >> + * > >> + * The size value returned by > >> KVM_CHECK_EXTENSION(KVM_CAP_XSAVE2) > >> + * will always be at least 4096. Currently, it is only greater > >> + * than 4096 if a dynamic feature has been enabled with > >> + * ``arch_prctl()``, but this may change in the future. > >> + * > >> + * The offsets of the state save areas in struct kvm_xsave follow > >> + * the contents of CPUID leaf 0xD on the host. > >> + */ > >> + __u32 extra[0]; > >> }; > >> > >> #define KVM_MAX_XCRS 16 > >> diff --git a/linux-headers/linux/kvm.h b/linux-headers/linux/kvm.h > >> index 02c5e7b7bb..97d5b6d81d 100644 > >> --- a/linux-headers/linux/kvm.h > >> +++ b/linux-headers/linux/kvm.h > >> @@ -1130,6 +1130,7 @@ struct kvm_ppc_resize_hpt { > >> #define KVM_CAP_BINARY_STATS_FD 203 > >> #define KVM_CAP_EXIT_ON_EMULATION_FAILURE 204 > >> #define KVM_CAP_ARM_MTE 205 > >> +#define KVM_CAP_XSAVE2 207 > >> > >> #ifdef KVM_CAP_IRQ_ROUTING > >> > >> @@ -1550,6 +1551,7 @@ struct kvm_s390_ucas_mapping { > >> /* Available with KVM_CAP_XSAVE */ > >> #define KVM_GET_XSAVE _IOR(KVMIO, 0xa4, struct > >> kvm_xsave) > >> #define KVM_SET_XSAVE _IOW(KVMIO, 0xa5, struct > >> kvm_xsave) > >> +#define KVM_GET_XSAVE2 _IOR(KVMIO, 0xcf, struct > >> kvm_xsave) > >> /* Available with KVM_CAP_XCRS */ > >> #define KVM_GET_XCRS _IOR(KVMIO, 0xa6, struct kvm_xcrs) > >> #define KVM_SET_XCRS _IOW(KVMIO, 0xa7, struct kvm_xcrs) > >> diff --git a/target/i386/cpu.h b/target/i386/cpu.h > >> index 245e8b5a1a..6153c4ab1a 100644 > >> --- a/target/i386/cpu.h > >> +++ b/target/i386/cpu.h > >> @@ -1519,6 +1519,11 @@ typedef struct CPUX86State { > >> YMMReg zmmh_regs[CPU_NB_REGS]; > >> ZMMReg hi16_zmm_regs[CPU_NB_REGS]; > >> > >> +#ifdef TARGET_X86_64 > >> + uint8_t xtilecfg[64]; > >> + uint8_t xtiledata[8192]; > >> +#endif > >> + > >> /* sysenter registers */ > >> uint32_t sysenter_cs; > >> target_ulong sysenter_esp; > >> diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c > >> index 3fb3ddbe2b..97520e9dff 100644 > >> --- a/target/i386/kvm/kvm.c > >> +++ b/target/i386/kvm/kvm.c > >> @@ -1983,7 +1983,12 @@ int kvm_arch_init_vcpu(CPUState *cs) > >> } > >> > >> if (has_xsave) { > >> - env->xsave_buf_len = sizeof(struct kvm_xsave); > >> + uint32_t size = kvm_vm_check_extension(cs->kvm_state, > >> KVM_CAP_XSAVE2); > >> + if (!size) { > >> + size = sizeof(struct kvm_xsave); > >> + } > >> + > >> + env->xsave_buf_len = QEMU_ALIGN_UP(size, 4096); > >> env->xsave_buf = qemu_memalign(4096, env->xsave_buf_len); > >> memset(env->xsave_buf, 0, env->xsave_buf_len); > >> > >> @@ -2580,6 +2585,7 @@ static int kvm_put_xsave(X86CPU *cpu) > >> if (!has_xsave) { > >> return kvm_put_fpu(cpu); > >> } > >> + > >> x86_cpu_xsave_all_areas(cpu, xsave, env->xsave_buf_len); > >> > >> return kvm_vcpu_ioctl(CPU(cpu), KVM_SET_XSAVE, xsave); > >> @@ -3247,10 +3253,16 @@ static int kvm_get_xsave(X86CPU *cpu) > >> return kvm_get_fpu(cpu); > >> } > >> > >> - ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE, xsave); > >> + if (env->xsave_buf_len <= sizeof(struct kvm_xsave)) { > >> + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE, xsave); > >> + } else { > >> + ret = kvm_vcpu_ioctl(CPU(cpu), KVM_GET_XSAVE2, xsave); > >> + } > >> + > >> if (ret < 0) { > >> return ret; > >> } > >> + > >> x86_cpu_xrstor_all_areas(cpu, xsave, env->xsave_buf_len); > >> > >> return 0; > >> diff --git a/target/i386/xsave_helper.c b/target/i386/xsave_helper.c > >> index ac61a96344..090424e820 100644 > >> --- a/target/i386/xsave_helper.c > >> +++ b/target/i386/xsave_helper.c > >> @@ -5,6 +5,7 @@ > >> #include "qemu/osdep.h" > >> > >> #include "cpu.h" > >> +#include <asm/kvm.h> > >> > >> void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen) > >> { > >> @@ -126,6 +127,23 @@ void x86_cpu_xsave_all_areas(X86CPU *cpu, > void > >> *buf, uint32_t buflen) > >> > >> memcpy(pkru, &env->pkru, sizeof(env->pkru)); > >> } > >> + > >> + e = &x86_ext_save_areas[XSTATE_XTILE_CFG_BIT]; > >> + if (e->size && e->offset) { > >> + XSaveXTILE_CFG *tilecfg = buf + e->offset; > >> + > >> + memcpy(tilecfg, &env->xtilecfg, sizeof(env->xtilecfg)); > >> + } > >> + > >> + if (buflen > sizeof(struct kvm_xsave)) { > >> + e = &x86_ext_save_areas[XSTATE_XTILE_DATA_BIT]; > >> + > >> + if (e->size && e->offset) { > >> + XSaveXTILE_DATA *tiledata = buf + e->offset; > >> + > >> + memcpy(tiledata, &env->xtiledata, sizeof(env->xtiledata)); > >> + } > >> + } > >> #endif > >> } > >> > >> @@ -247,5 +265,22 @@ void x86_cpu_xrstor_all_areas(X86CPU *cpu, > const > >> void *buf, uint32_t buflen) > >> pkru = buf + e->offset; > >> memcpy(&env->pkru, pkru, sizeof(env->pkru)); > >> } > >> + > >> + e = &x86_ext_save_areas[XSTATE_XTILE_CFG_BIT]; > >> + if (e->size && e->offset) { > >> + const XSaveXTILE_CFG *tilecfg = buf + e->offset; > >> + > >> + memcpy(&env->xtilecfg, tilecfg, sizeof(env->xtilecfg)); > >> + } > >> + > >> + if (buflen > sizeof(struct kvm_xsave)) { > >> + e = &x86_ext_save_areas[XSTATE_XTILE_DATA_BIT]; > >> + > >> + if (e->size && e->offset) { > >> + const XSaveXTILE_DATA *tiledata = buf + e->offset; > >> + > >> + memcpy(&env->xtiledata, tiledata, sizeof(env->xtiledata)); > >> + } > >> + } > >> #endif > >> }