From c32bda382df1bd5e5384c0635d3a968010165d98 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Fri, 15 Oct 2021 03:16:17 +0200 Subject: [PATCH] x86/fpu: Replace KVMs home brewed FPU copy to user mainline inclusion from mainline-v5.16-rc1 commit bf5d00470787067ff27593c6a097b5eb6e01168e category: feature bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I590ZC CVE: NA Intel-SIG: commit bf5d00470787 x86/fpu: Replace KVMs home brewed FPU copy to user. -------------------------------- Similar to the copy from user function the FPU core has this already implemented with all bells and whistles. Get rid of the duplicated code and use the core functionality. Signed-off-by: Thomas Gleixner Signed-off-by: Borislav Petkov Cc: kvm@vger.kernel.org Link: https://lkml.kernel.org/r/20211015011539.244101845@linutronix.de Signed-off-by: Lin Wang Signed-off-by: Aichun Shi --- arch/x86/include/asm/fpu/api.h | 1 + arch/x86/kernel/fpu/core.c | 18 +++++++++++ arch/x86/kvm/x86.c | 56 ++-------------------------------- 3 files changed, 22 insertions(+), 53 deletions(-) diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index a1f197ff401b..360cef8367a7 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -110,5 +110,6 @@ extern void fpu_init_fpstate_user(struct fpu *fpu); extern void fpu_swap_kvm_fpu(struct fpu *save, struct fpu *rstor, u64 restore_mask); extern int fpu_copy_kvm_uabi_to_fpstate(struct fpu *fpu, const void *buf, u64 xcr0, u32 *pkru); +extern void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf, unsigned int size, u32 pkru); #endif /* _ASM_X86_FPU_API_H */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 79f2e8ddd10c..ac540a7d410e 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -184,6 +184,24 @@ void fpu_swap_kvm_fpu(struct fpu *save, struct fpu *rstor, u64 restore_mask) } EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpu); +void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf, + unsigned int size, u32 pkru) +{ + union fpregs_state *kstate = &fpu->state; + union fpregs_state *ustate = buf; + struct membuf mb = { .p = buf, .left = size }; + + if (cpu_feature_enabled(X86_FEATURE_XSAVE)) { + __copy_xstate_to_uabi_buf(mb, &kstate->xsave, pkru, + XSTATE_COPY_XSAVE); + } else { + memcpy(&ustate->fxsave, &kstate->fxsave, sizeof(ustate->fxsave)); + /* Make it restorable on a XSAVE enabled host */ + ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE; + } +} +EXPORT_SYMBOL_GPL(fpu_copy_fpstate_to_kvm_uabi); + int fpu_copy_kvm_uabi_to_fpstate(struct fpu *fpu, const void *buf, u64 xcr0, u32 *vpkru) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 08efe436b10e..ec9c6c3bb64a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4581,62 +4581,12 @@ static int kvm_vcpu_ioctl_x86_set_debugregs(struct kvm_vcpu *vcpu, return 0; } -static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) -{ - struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave; - u64 xstate_bv = xsave->header.xfeatures; - u64 valid; - - /* - * Copy legacy XSAVE area, to avoid complications with CPUID - * leaves 0 and 1 in the loop below. - */ - memcpy(dest, xsave, XSAVE_HDR_OFFSET); - - /* Set XSTATE_BV */ - xstate_bv &= vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FPSSE; - *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv; - - /* - * Copy each region from the possibly compacted offset to the - * non-compacted offset. - */ - valid = xstate_bv & ~XFEATURE_MASK_FPSSE; - while (valid) { - u32 size, offset, ecx, edx; - u64 xfeature_mask = valid & -valid; - int xfeature_nr = fls64(xfeature_mask) - 1; - void *src; - - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - - if (xfeature_nr == XFEATURE_PKRU) { - memcpy(dest + offset, &vcpu->arch.pkru, - sizeof(vcpu->arch.pkru)); - } else { - src = get_xsave_addr(xsave, xfeature_nr); - if (src) - memcpy(dest + offset, src, size); - } - - valid -= xfeature_mask; - } -} - static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { - if (boot_cpu_has(X86_FEATURE_XSAVE)) { - memset(guest_xsave, 0, sizeof(struct kvm_xsave)); - fill_xsave((u8 *) guest_xsave->region, vcpu); - } else { - memcpy(guest_xsave->region, - &vcpu->arch.guest_fpu->state.fxsave, - sizeof(struct fxregs_state)); - *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] = - XFEATURE_MASK_FPSSE; - } + fpu_copy_fpstate_to_kvm_uabi(vcpu->arch.guest_fpu, guest_xsave->region, + sizeof(guest_xsave->region), + vcpu->arch.pkru); } static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu, -- GitLab