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Date: Wed, 9 Nov 2016 19:46:28 +0100
From: Radim Krčmář <rkrcmar@...hat.com>
To: kbuild test robot <lkp@...el.com>
Cc: kbuild-all@...org, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
Bandan Das <bsd@...hat.com>, Nadav Amit <nadav.amit@...il.com>
Subject: Re: [PATCH v4] KVM: x86: emulate FXSAVE and FXRSTOR
2016-11-10 02:42+0800, kbuild test robot:
> Hi Radim,
And I even replied to the series, so this would happen ...
Btw. would the tool recognize it if the header was [PATCH v4 4/4]?
> [auto build test ERROR on kvm/linux-next]
> [also build test ERROR on v4.9-rc4 next-20161109]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Radim-Kr-m/KVM-x86-emulate-FXSAVE-and-FXRSTOR/20161110-021048
> base: https://git.kernel.org/pub/scm/virt/kvm/kvm.git linux-next
> config: x86_64-randconfig-x018-201645 (attached as .config)
> compiler: gcc-6 (Debian 6.2.0-3) 6.2.0 20160901
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=x86_64
>
> All errors (new ones prefixed by >>):
>
> arch/x86/kvm/emulate.c: In function 'em_fxsave':
> >> arch/x86/kvm/emulate.c:3910:7: error: implicit declaration of function 'asm_safe' [-Werror=implicit-function-declaration]
> rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));
> ^~~~~~~~
> >> arch/x86/kvm/emulate.c:3910:32: error: expected expression before ',' token
> rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));
> ^
> >> arch/x86/kvm/emulate.c:3910:35: error: 'fx' undeclared (first use in this function)
> rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));
> ^~
> arch/x86/kvm/emulate.c:3910:35: note: each undeclared identifier is reported only once for each function it appears in
> arch/x86/kvm/emulate.c: In function 'fxrstor_fixup':
> arch/x86/kvm/emulate.c:3931:32: error: expected expression before ',' token
> rc = asm_safe("fxsave %[fx]", , [fx] "+m"(old));
> ^
> arch/x86/kvm/emulate.c:3931:35: error: 'fx' undeclared (first use in this function)
> rc = asm_safe("fxsave %[fx]", , [fx] "+m"(old));
> ^~
> arch/x86/kvm/emulate.c: In function 'em_fxrstor':
> >> arch/x86/kvm/emulate.c:3977:34: error: expected expression before ':' token
> rc = asm_safe("fxrstor %[fx]", : [fx] "m"(fx_state));
> ^
> arch/x86/kvm/emulate.c: At top level:
> >> arch/x86/kvm/emulate.c:4336:12: error: 'Aligned16' undeclared here (not in a function)
> I(ModRM | Aligned16, em_fxsave),
> ^
> arch/x86/kvm/emulate.c:4185:31: note: in definition of macro 'I'
> #define I(_f, _e) { .flags = (_f), .u.execute = (_e) }
> ^~
> cc1: some warnings being treated as errors
>
> vim +/asm_safe +3910 arch/x86/kvm/emulate.c
>
> 3904 rc = check_fxsr(ctxt);
> 3905 if (rc != X86EMUL_CONTINUE)
> 3906 return rc;
> 3907
> 3908 ctxt->ops->get_fpu(ctxt);
> 3909
> > 3910 rc = asm_safe("fxsave %[fx]", , [fx] "+m"(fx_state));
> 3911
> 3912 ctxt->ops->put_fpu(ctxt);
> 3913
> 3914 if (rc != X86EMUL_CONTINUE)
> 3915 return rc;
> 3916
> 3917 if (ctxt->ops->get_cr(ctxt, 4) & X86_CR4_OSFXSR)
> 3918 size = offsetof(struct fxregs_state, xmm_space[8 * 16/4]);
> 3919 else
> 3920 size = offsetof(struct fxregs_state, xmm_space[0]);
> 3921
> 3922 return segmented_write(ctxt, ctxt->memop.addr.mem, &fx_state, size);
> 3923 }
> 3924
> 3925 static int fxrstor_fixup(struct x86_emulate_ctxt *ctxt,
> 3926 struct fxregs_state *new)
> 3927 {
> 3928 int rc = X86EMUL_CONTINUE;
> 3929 struct fxregs_state old;
> 3930
> > 3931 rc = asm_safe("fxsave %[fx]", , [fx] "+m"(old));
> 3932 if (rc != X86EMUL_CONTINUE)
> 3933 return rc;
> 3934
> 3935 /*
> 3936 * 64 bit host will restore XMM 8-15, which is not correct on non-64
> 3937 * bit guests. Load the current values in order to preserve 64 bit
> 3938 * XMMs after fxrstor.
> 3939 */
> 3940 #ifdef CONFIG_X86_64
> 3941 /* XXX: accessing XMM 8-15 very awkwardly */
> 3942 memcpy(&new->xmm_space[8 * 16/4], &old.xmm_space[8 * 16/4], 8 * 16);
> 3943 #endif
> 3944
> 3945 /*
> 3946 * Hardware doesn't save and restore XMM 0-7 without CR4.OSFXSR, but
> 3947 * does save and restore MXCSR.
> 3948 */
> 3949 if (!(ctxt->ops->get_cr(ctxt, 4) & X86_CR4_OSFXSR))
> 3950 memcpy(new->xmm_space, old.xmm_space, 8 * 16);
> 3951
> 3952 return rc;
> 3953 }
> 3954
> 3955 static int em_fxrstor(struct x86_emulate_ctxt *ctxt)
> 3956 {
> 3957 struct fxregs_state fx_state;
> 3958 int rc;
> 3959
> 3960 rc = check_fxsr(ctxt);
> 3961 if (rc != X86EMUL_CONTINUE)
> 3962 return rc;
> 3963
> 3964 rc = segmented_read(ctxt, ctxt->memop.addr.mem, &fx_state, 512);
> 3965 if (rc != X86EMUL_CONTINUE)
> 3966 return rc;
> 3967
> 3968 if (fx_state.mxcsr >> 16)
> 3969 return emulate_gp(ctxt, 0);
> 3970
> 3971 ctxt->ops->get_fpu(ctxt);
> 3972
> 3973 if (ctxt->mode < X86EMUL_MODE_PROT64)
> 3974 rc = fxrstor_fixup(ctxt, &fx_state);
> 3975
> 3976 if (rc == X86EMUL_CONTINUE)
> > 3977 rc = asm_safe("fxrstor %[fx]", : [fx] "m"(fx_state));
> 3978
> 3979 ctxt->ops->put_fpu(ctxt);
> 3980
>
> ---
> 0-DAY kernel test infrastructure Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all Intel Corporation
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