Hi Yuchen, On 5/17/23 03:55, Yuchen wrote: > Migrating guest from Intel new CPU (as Gold 6230) to old CPU (as > E5-2650 v4) will pause on the destination host. Because old CPU > not support xsave pkru feature, and KVM KVM_SET_XSAVE ioctl > return EINVAL. > > This kernel commit introduces the problem: > ea4d6938d4c0 x86/fpu: Replace KVMs home brewed FPU copy from user
This kernel commit issue should be resolved by the below kernel commit. x86/kvm/fpu: Limit guest user_xfeatures to supported bits of XCR0 https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ad856280ddea3401e1f5060ef20e6de9f6122c76 Since the old target server does not support pkru, I assume the VM's cpu type should not support pkru. Therefore, the pkru should never be migrated away from source server. Dongli Zhang > > Signed-off-by: YuChen <yu.c...@h3c.com> > --- > target/i386/xsave_helper.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/target/i386/xsave_helper.c b/target/i386/xsave_helper.c > index 996e9f3bfe..64e2b969fe 100644 > --- a/target/i386/xsave_helper.c > +++ b/target/i386/xsave_helper.c > @@ -6,6 +6,8 @@ > #include "cpu.h" > +static bool has_xsave_pkru; > + > void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, uint32_t buflen) > { > CPUX86State *env = &cpu->env; > @@ -47,6 +49,9 @@ void x86_cpu_xsave_all_areas(X86CPU *cpu, void *buf, > uint32_t buflen) > stq_p(xmm + 8, env->xmm_regs[i].ZMM_Q(1)); > } > + if (!has_xsave_pkru) { > + env->xstate_bv &= ~XSTATE_PKRU_MASK; > + } > header->xstate_bv = env->xstate_bv; > e = &x86_ext_save_areas[XSTATE_YMM_BIT]; > @@ -181,6 +186,9 @@ void x86_cpu_xrstor_all_areas(X86CPU *cpu, const void > *buf, uint32_t buflen) > env->xmm_regs[i].ZMM_Q(1) = ldq_p(xmm + 8); > } > + if (xsave->header.xstate_bv & XSTATE_PKRU_MASK) { > + has_xsave_pkru = true; > + } > env->xstate_bv = header->xstate_bv; > e = &x86_ext_save_areas[XSTATE_YMM_BIT]; > -- > 2.34.1 > ------------------------------------------------------------------------------------------------------------------------------------- > ????????????????????????????????? > ???????????????????????????????????????? > ???????????????????????????????????????? > ??? > This e-mail and its attachments contain confidential information from New > H3C, which is > intended only for the person or entity whose address is listed above. Any use > of the > information contained herein in any way (including, but not limited to, total > or partial > disclosure, reproduction, or dissemination) by persons other than the intended > recipient(s) is prohibited. If you receive this e-mail in error, please > notify the sender > by phone or email immediately and delete it! >
