From bc8a3d8925a8fa09fa550e0da115d95851ce33c6 Mon Sep 17 00:00:00 2001 From: Ben Gardon Date: Mon, 8 Apr 2019 11:07:30 -0700 Subject: kvm: mmu: Fix overflow on kvm mmu page limit calculation KVM bases its memory usage limits on the total number of guest pages across all memslots. However, those limits, and the calculations to produce them, use 32 bit unsigned integers. This can result in overflow if a VM has more guest pages that can be represented by a u32. As a result of this overflow, KVM can use a low limit on the number of MMU pages it will allocate. This makes KVM unable to map all of guest memory at once, prompting spurious faults. Tested: Ran all kvm-unit-tests on an Intel Haswell machine. This patch introduced no new failures. Signed-off-by: Ben Gardon Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 099b851dabaf..455f156f56ed 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4270,7 +4270,7 @@ static int kvm_vm_ioctl_set_identity_map_addr(struct kvm *kvm, } static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, - u32 kvm_nr_mmu_pages) + unsigned long kvm_nr_mmu_pages) { if (kvm_nr_mmu_pages < KVM_MIN_ALLOC_MMU_PAGES) return -EINVAL; @@ -4284,7 +4284,7 @@ static int kvm_vm_ioctl_set_nr_mmu_pages(struct kvm *kvm, return 0; } -static int kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm) +static unsigned long kvm_vm_ioctl_get_nr_mmu_pages(struct kvm *kvm) { return kvm->arch.n_max_mmu_pages; } -- cgit v1.2.3-55-g7522 From 1811d979c71621aafc7b879477202d286f7e863b Mon Sep 17 00:00:00 2001 From: WANG Chao Date: Fri, 12 Apr 2019 15:55:39 +0800 Subject: x86/kvm: move kvm_load/put_guest_xcr0 into atomic context guest xcr0 could leak into host when MCE happens in guest mode. Because do_machine_check() could schedule out at a few places. For example: kvm_load_guest_xcr0 ... kvm_x86_ops->run(vcpu) { vmx_vcpu_run vmx_complete_atomic_exit kvm_machine_check do_machine_check do_memory_failure memory_failure lock_page In this case, host_xcr0 is 0x2ff, guest vcpu xcr0 is 0xff. After schedule out, host cpu has guest xcr0 loaded (0xff). In __switch_to { switch_fpu_finish copy_kernel_to_fpregs XRSTORS If any bit i in XSTATE_BV[i] == 1 and xcr0[i] == 0, XRSTORS will generate #GP (In this case, bit 9). Then ex_handler_fprestore kicks in and tries to reinitialize fpu by restoring init fpu state. Same story as last #GP, except we get DOUBLE FAULT this time. Cc: stable@vger.kernel.org Signed-off-by: WANG Chao Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 2 ++ arch/x86/kvm/vmx/vmx.c | 4 ++++ arch/x86/kvm/x86.c | 10 ++++------ arch/x86/kvm/x86.h | 2 ++ 4 files changed, 12 insertions(+), 6 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index c6815aef2cac..675cecb3fa9c 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -5636,6 +5636,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) svm->vmcb->save.cr2 = vcpu->arch.cr2; clgi(); + kvm_load_guest_xcr0(vcpu); /* * If this vCPU has touched SPEC_CTRL, restore the guest's value if @@ -5781,6 +5782,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu) if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI)) kvm_before_interrupt(&svm->vcpu); + kvm_put_guest_xcr0(vcpu); stgi(); /* Any pending NMI will happen here */ diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 7a8f75fc6b7e..88060a621db2 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -6410,6 +6410,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) vmx_set_interrupt_shadow(vcpu, 0); + kvm_load_guest_xcr0(vcpu); + if (static_cpu_has(X86_FEATURE_PKU) && kvm_read_cr4_bits(vcpu, X86_CR4_PKE) && vcpu->arch.pkru != vmx->host_pkru) @@ -6506,6 +6508,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu) __write_pkru(vmx->host_pkru); } + kvm_put_guest_xcr0(vcpu); + vmx->nested.nested_run_pending = 0; vmx->idt_vectoring_info = 0; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 455f156f56ed..f05891b8df7c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -800,7 +800,7 @@ void kvm_lmsw(struct kvm_vcpu *vcpu, unsigned long msw) } EXPORT_SYMBOL_GPL(kvm_lmsw); -static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu) +void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu) { if (kvm_read_cr4_bits(vcpu, X86_CR4_OSXSAVE) && !vcpu->guest_xcr0_loaded) { @@ -810,8 +810,9 @@ static void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu) vcpu->guest_xcr0_loaded = 1; } } +EXPORT_SYMBOL_GPL(kvm_load_guest_xcr0); -static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) +void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) { if (vcpu->guest_xcr0_loaded) { if (vcpu->arch.xcr0 != host_xcr0) @@ -819,6 +820,7 @@ static void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu) vcpu->guest_xcr0_loaded = 0; } } +EXPORT_SYMBOL_GPL(kvm_put_guest_xcr0); static int __kvm_set_xcr(struct kvm_vcpu *vcpu, u32 index, u64 xcr) { @@ -7865,8 +7867,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) goto cancel_injection; } - kvm_load_guest_xcr0(vcpu); - if (req_immediate_exit) { kvm_make_request(KVM_REQ_EVENT, vcpu); kvm_x86_ops->request_immediate_exit(vcpu); @@ -7919,8 +7919,6 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) vcpu->mode = OUTSIDE_GUEST_MODE; smp_wmb(); - kvm_put_guest_xcr0(vcpu); - kvm_before_interrupt(vcpu); kvm_x86_ops->handle_external_intr(vcpu); kvm_after_interrupt(vcpu); diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h index 28406aa1136d..aedc5d0d4989 100644 --- a/arch/x86/kvm/x86.h +++ b/arch/x86/kvm/x86.h @@ -347,4 +347,6 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu) __this_cpu_write(current_vcpu, NULL); } +void kvm_load_guest_xcr0(struct kvm_vcpu *vcpu); +void kvm_put_guest_xcr0(struct kvm_vcpu *vcpu); #endif -- cgit v1.2.3-55-g7522 From ed19321fb6571214f410b30322e4ad6e6b7c3915 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 2 Apr 2019 08:03:09 -0700 Subject: KVM: x86: Load SMRAM in a single shot when leaving SMM RSM emulation is currently broken on VMX when the interrupted guest has CR4.VMXE=1. Rather than dance around the issue of HF_SMM_MASK being set when loading SMSTATE into architectural state, ideally RSM emulation itself would be reworked to clear HF_SMM_MASK prior to loading non-SMM architectural state. Ostensibly, the only motivation for having HF_SMM_MASK set throughout the loading of state from the SMRAM save state area is so that the memory accesses from GET_SMSTATE() are tagged with role.smm. Load all of the SMRAM save state area from guest memory at the beginning of RSM emulation, and load state from the buffer instead of reading guest memory one-by-one. This paves the way for clearing HF_SMM_MASK prior to loading state, and also aligns RSM with the enter_smm() behavior, which fills a buffer and writes SMRAM save state in a single go. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_emulate.h | 3 +- arch/x86/include/asm/kvm_host.h | 5 +- arch/x86/kvm/emulate.c | 149 ++++++++++++++++++------------------- arch/x86/kvm/svm.c | 20 ++--- arch/x86/kvm/vmx/vmx.c | 2 +- arch/x86/kvm/x86.c | 5 +- 6 files changed, 92 insertions(+), 92 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index 93c4bf598fb0..ec489c432850 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -226,7 +226,8 @@ struct x86_emulate_ops { unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt); void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags); - int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, u64 smbase); + int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, + const char *smstate); }; diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 9b7b731a0032..a9d03af34030 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -1182,7 +1182,7 @@ struct kvm_x86_ops { int (*smi_allowed)(struct kvm_vcpu *vcpu); int (*pre_enter_smm)(struct kvm_vcpu *vcpu, char *smstate); - int (*pre_leave_smm)(struct kvm_vcpu *vcpu, u64 smbase); + int (*pre_leave_smm)(struct kvm_vcpu *vcpu, const char *smstate); int (*enable_smi_window)(struct kvm_vcpu *vcpu); int (*mem_enc_op)(struct kvm *kvm, void __user *argp); @@ -1592,4 +1592,7 @@ static inline int kvm_cpu_get_apicid(int mps_cpu) #define put_smstate(type, buf, offset, val) \ *(type *)((buf) + (offset) - 0x7e00) = val +#define GET_SMSTATE(type, buf, offset) \ + (*(type *)((buf) + (offset) - 0x7e00)) + #endif /* _ASM_X86_KVM_HOST_H */ diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index c338984c850d..ae0d289b50fe 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2339,16 +2339,6 @@ static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt) return edx & bit(X86_FEATURE_LM); } -#define GET_SMSTATE(type, smbase, offset) \ - ({ \ - type __val; \ - int r = ctxt->ops->read_phys(ctxt, smbase + offset, &__val, \ - sizeof(__val)); \ - if (r != X86EMUL_CONTINUE) \ - return X86EMUL_UNHANDLEABLE; \ - __val; \ - }) - static void rsm_set_desc_flags(struct desc_struct *desc, u32 flags) { desc->g = (flags >> 23) & 1; @@ -2361,27 +2351,29 @@ static void rsm_set_desc_flags(struct desc_struct *desc, u32 flags) desc->type = (flags >> 8) & 15; } -static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, u64 smbase, int n) +static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, const char *smstate, + int n) { struct desc_struct desc; int offset; u16 selector; - selector = GET_SMSTATE(u32, smbase, 0x7fa8 + n * 4); + selector = GET_SMSTATE(u32, smstate, 0x7fa8 + n * 4); if (n < 3) offset = 0x7f84 + n * 12; else offset = 0x7f2c + (n - 3) * 12; - set_desc_base(&desc, GET_SMSTATE(u32, smbase, offset + 8)); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, offset + 4)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smbase, offset)); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, offset + 8)); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, offset + 4)); + rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, offset)); ctxt->ops->set_segment(ctxt, selector, &desc, 0, n); return X86EMUL_CONTINUE; } -static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n) +static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, const char *smstate, + int n) { struct desc_struct desc; int offset; @@ -2390,11 +2382,11 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, u64 smbase, int n) offset = 0x7e00 + n * 16; - selector = GET_SMSTATE(u16, smbase, offset); - rsm_set_desc_flags(&desc, GET_SMSTATE(u16, smbase, offset + 2) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, offset + 4)); - set_desc_base(&desc, GET_SMSTATE(u32, smbase, offset + 8)); - base3 = GET_SMSTATE(u32, smbase, offset + 12); + selector = GET_SMSTATE(u16, smstate, offset); + rsm_set_desc_flags(&desc, GET_SMSTATE(u16, smstate, offset + 2) << 8); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, offset + 4)); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, offset + 8)); + base3 = GET_SMSTATE(u32, smstate, offset + 12); ctxt->ops->set_segment(ctxt, selector, &desc, base3, n); return X86EMUL_CONTINUE; @@ -2445,7 +2437,8 @@ static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt, return X86EMUL_CONTINUE; } -static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase) +static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, + const char *smstate) { struct desc_struct desc; struct desc_ptr dt; @@ -2453,53 +2446,54 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, u64 smbase) u32 val, cr0, cr3, cr4; int i; - cr0 = GET_SMSTATE(u32, smbase, 0x7ffc); - cr3 = GET_SMSTATE(u32, smbase, 0x7ff8); - ctxt->eflags = GET_SMSTATE(u32, smbase, 0x7ff4) | X86_EFLAGS_FIXED; - ctxt->_eip = GET_SMSTATE(u32, smbase, 0x7ff0); + cr0 = GET_SMSTATE(u32, smstate, 0x7ffc); + cr3 = GET_SMSTATE(u32, smstate, 0x7ff8); + ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7ff4) | X86_EFLAGS_FIXED; + ctxt->_eip = GET_SMSTATE(u32, smstate, 0x7ff0); for (i = 0; i < 8; i++) - *reg_write(ctxt, i) = GET_SMSTATE(u32, smbase, 0x7fd0 + i * 4); + *reg_write(ctxt, i) = GET_SMSTATE(u32, smstate, 0x7fd0 + i * 4); - val = GET_SMSTATE(u32, smbase, 0x7fcc); + val = GET_SMSTATE(u32, smstate, 0x7fcc); ctxt->ops->set_dr(ctxt, 6, (val & DR6_VOLATILE) | DR6_FIXED_1); - val = GET_SMSTATE(u32, smbase, 0x7fc8); + val = GET_SMSTATE(u32, smstate, 0x7fc8); ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1); - selector = GET_SMSTATE(u32, smbase, 0x7fc4); - set_desc_base(&desc, GET_SMSTATE(u32, smbase, 0x7f64)); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, 0x7f60)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smbase, 0x7f5c)); + selector = GET_SMSTATE(u32, smstate, 0x7fc4); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7f64)); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7f60)); + rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7f5c)); ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_TR); - selector = GET_SMSTATE(u32, smbase, 0x7fc0); - set_desc_base(&desc, GET_SMSTATE(u32, smbase, 0x7f80)); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, 0x7f7c)); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smbase, 0x7f78)); + selector = GET_SMSTATE(u32, smstate, 0x7fc0); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7f80)); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7f7c)); + rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7f78)); ctxt->ops->set_segment(ctxt, selector, &desc, 0, VCPU_SREG_LDTR); - dt.address = GET_SMSTATE(u32, smbase, 0x7f74); - dt.size = GET_SMSTATE(u32, smbase, 0x7f70); + dt.address = GET_SMSTATE(u32, smstate, 0x7f74); + dt.size = GET_SMSTATE(u32, smstate, 0x7f70); ctxt->ops->set_gdt(ctxt, &dt); - dt.address = GET_SMSTATE(u32, smbase, 0x7f58); - dt.size = GET_SMSTATE(u32, smbase, 0x7f54); + dt.address = GET_SMSTATE(u32, smstate, 0x7f58); + dt.size = GET_SMSTATE(u32, smstate, 0x7f54); ctxt->ops->set_idt(ctxt, &dt); for (i = 0; i < 6; i++) { - int r = rsm_load_seg_32(ctxt, smbase, i); + int r = rsm_load_seg_32(ctxt, smstate, i); if (r != X86EMUL_CONTINUE) return r; } - cr4 = GET_SMSTATE(u32, smbase, 0x7f14); + cr4 = GET_SMSTATE(u32, smstate, 0x7f14); - ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7ef8)); + ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smstate, 0x7ef8)); return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); } -static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) +static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, + const char *smstate) { struct desc_struct desc; struct desc_ptr dt; @@ -2509,43 +2503,43 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) int i, r; for (i = 0; i < 16; i++) - *reg_write(ctxt, i) = GET_SMSTATE(u64, smbase, 0x7ff8 - i * 8); + *reg_write(ctxt, i) = GET_SMSTATE(u64, smstate, 0x7ff8 - i * 8); - ctxt->_eip = GET_SMSTATE(u64, smbase, 0x7f78); - ctxt->eflags = GET_SMSTATE(u32, smbase, 0x7f70) | X86_EFLAGS_FIXED; + ctxt->_eip = GET_SMSTATE(u64, smstate, 0x7f78); + ctxt->eflags = GET_SMSTATE(u32, smstate, 0x7f70) | X86_EFLAGS_FIXED; - val = GET_SMSTATE(u32, smbase, 0x7f68); + val = GET_SMSTATE(u32, smstate, 0x7f68); ctxt->ops->set_dr(ctxt, 6, (val & DR6_VOLATILE) | DR6_FIXED_1); - val = GET_SMSTATE(u32, smbase, 0x7f60); + val = GET_SMSTATE(u32, smstate, 0x7f60); ctxt->ops->set_dr(ctxt, 7, (val & DR7_VOLATILE) | DR7_FIXED_1); - cr0 = GET_SMSTATE(u64, smbase, 0x7f58); - cr3 = GET_SMSTATE(u64, smbase, 0x7f50); - cr4 = GET_SMSTATE(u64, smbase, 0x7f48); - ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smbase, 0x7f00)); - val = GET_SMSTATE(u64, smbase, 0x7ed0); + cr0 = GET_SMSTATE(u64, smstate, 0x7f58); + cr3 = GET_SMSTATE(u64, smstate, 0x7f50); + cr4 = GET_SMSTATE(u64, smstate, 0x7f48); + ctxt->ops->set_smbase(ctxt, GET_SMSTATE(u32, smstate, 0x7f00)); + val = GET_SMSTATE(u64, smstate, 0x7ed0); ctxt->ops->set_msr(ctxt, MSR_EFER, val & ~EFER_LMA); - selector = GET_SMSTATE(u32, smbase, 0x7e90); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smbase, 0x7e92) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, 0x7e94)); - set_desc_base(&desc, GET_SMSTATE(u32, smbase, 0x7e98)); - base3 = GET_SMSTATE(u32, smbase, 0x7e9c); + selector = GET_SMSTATE(u32, smstate, 0x7e90); + rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7e92) << 8); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7e94)); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7e98)); + base3 = GET_SMSTATE(u32, smstate, 0x7e9c); ctxt->ops->set_segment(ctxt, selector, &desc, base3, VCPU_SREG_TR); - dt.size = GET_SMSTATE(u32, smbase, 0x7e84); - dt.address = GET_SMSTATE(u64, smbase, 0x7e88); + dt.size = GET_SMSTATE(u32, smstate, 0x7e84); + dt.address = GET_SMSTATE(u64, smstate, 0x7e88); ctxt->ops->set_idt(ctxt, &dt); - selector = GET_SMSTATE(u32, smbase, 0x7e70); - rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smbase, 0x7e72) << 8); - set_desc_limit(&desc, GET_SMSTATE(u32, smbase, 0x7e74)); - set_desc_base(&desc, GET_SMSTATE(u32, smbase, 0x7e78)); - base3 = GET_SMSTATE(u32, smbase, 0x7e7c); + selector = GET_SMSTATE(u32, smstate, 0x7e70); + rsm_set_desc_flags(&desc, GET_SMSTATE(u32, smstate, 0x7e72) << 8); + set_desc_limit(&desc, GET_SMSTATE(u32, smstate, 0x7e74)); + set_desc_base(&desc, GET_SMSTATE(u32, smstate, 0x7e78)); + base3 = GET_SMSTATE(u32, smstate, 0x7e7c); ctxt->ops->set_segment(ctxt, selector, &desc, base3, VCPU_SREG_LDTR); - dt.size = GET_SMSTATE(u32, smbase, 0x7e64); - dt.address = GET_SMSTATE(u64, smbase, 0x7e68); + dt.size = GET_SMSTATE(u32, smstate, 0x7e64); + dt.address = GET_SMSTATE(u64, smstate, 0x7e68); ctxt->ops->set_gdt(ctxt, &dt); r = rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); @@ -2553,7 +2547,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) return r; for (i = 0; i < 6; i++) { - r = rsm_load_seg_64(ctxt, smbase, i); + r = rsm_load_seg_64(ctxt, smstate, i); if (r != X86EMUL_CONTINUE) return r; } @@ -2564,12 +2558,19 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, u64 smbase) static int em_rsm(struct x86_emulate_ctxt *ctxt) { unsigned long cr0, cr4, efer; + char buf[512]; u64 smbase; int ret; if ((ctxt->ops->get_hflags(ctxt) & X86EMUL_SMM_MASK) == 0) return emulate_ud(ctxt); + smbase = ctxt->ops->get_smbase(ctxt); + + ret = ctxt->ops->read_phys(ctxt, smbase + 0xfe00, buf, sizeof(buf)); + if (ret != X86EMUL_CONTINUE) + return X86EMUL_UNHANDLEABLE; + /* * Get back to real mode, to prepare a safe state in which to load * CR0/CR3/CR4/EFER. It's all a bit more complicated if the vCPU @@ -2605,20 +2606,18 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt) efer = 0; ctxt->ops->set_msr(ctxt, MSR_EFER, efer); - smbase = ctxt->ops->get_smbase(ctxt); - /* * Give pre_leave_smm() a chance to make ISA-specific changes to the * vCPU state (e.g. enter guest mode) before loading state from the SMM * state-save area. */ - if (ctxt->ops->pre_leave_smm(ctxt, smbase)) + if (ctxt->ops->pre_leave_smm(ctxt, buf)) return X86EMUL_UNHANDLEABLE; if (emulator_has_longmode(ctxt)) - ret = rsm_load_state_64(ctxt, smbase + 0x8000); + ret = rsm_load_state_64(ctxt, buf); else - ret = rsm_load_state_32(ctxt, smbase + 0x8000); + ret = rsm_load_state_32(ctxt, buf); if (ret != X86EMUL_CONTINUE) { /* FIXME: should triple fault */ diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 675cecb3fa9c..6b1cd73e4053 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -6232,27 +6232,23 @@ static int svm_pre_enter_smm(struct kvm_vcpu *vcpu, char *smstate) return 0; } -static int svm_pre_leave_smm(struct kvm_vcpu *vcpu, u64 smbase) +static int svm_pre_leave_smm(struct kvm_vcpu *vcpu, const char *smstate) { struct vcpu_svm *svm = to_svm(vcpu); struct vmcb *nested_vmcb; struct page *page; - struct { - u64 guest; - u64 vmcb; - } svm_state_save; + u64 guest; + u64 vmcb; int ret; - ret = kvm_vcpu_read_guest(vcpu, smbase + 0xfed8, &svm_state_save, - sizeof(svm_state_save)); - if (ret) - return ret; + guest = GET_SMSTATE(u64, smstate, 0x7ed8); + vmcb = GET_SMSTATE(u64, smstate, 0x7ee0); - if (svm_state_save.guest) { + if (guest) { vcpu->arch.hflags &= ~HF_SMM_MASK; - nested_vmcb = nested_svm_map(svm, svm_state_save.vmcb, &page); + nested_vmcb = nested_svm_map(svm, vmcb, &page); if (nested_vmcb) - enter_svm_guest_mode(svm, svm_state_save.vmcb, nested_vmcb, page); + enter_svm_guest_mode(svm, vmcb, nested_vmcb, page); else ret = 1; vcpu->arch.hflags |= HF_SMM_MASK; diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 5866e9e9f1e0..14ea25eadde8 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7398,7 +7398,7 @@ static int vmx_pre_enter_smm(struct kvm_vcpu *vcpu, char *smstate) return 0; } -static int vmx_pre_leave_smm(struct kvm_vcpu *vcpu, u64 smbase) +static int vmx_pre_leave_smm(struct kvm_vcpu *vcpu, const char *smstate) { struct vcpu_vmx *vmx = to_vmx(vcpu); int ret; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f05891b8df7c..6ee1f9e5d3fb 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5963,9 +5963,10 @@ static void emulator_set_hflags(struct x86_emulate_ctxt *ctxt, unsigned emul_fla kvm_set_hflags(emul_to_vcpu(ctxt), emul_flags); } -static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, u64 smbase) +static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, + const char *smstate) { - return kvm_x86_ops->pre_leave_smm(emul_to_vcpu(ctxt), smbase); + return kvm_x86_ops->pre_leave_smm(emul_to_vcpu(ctxt), smstate); } static const struct x86_emulate_ops emulate_ops = { -- cgit v1.2.3-55-g7522 From c5833c7a43a66bfe2f36439cb2f1281a588668af Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 2 Apr 2019 08:03:10 -0700 Subject: KVM: x86: Open code kvm_set_hflags Prepare for clearing HF_SMM_MASK prior to loading state from the SMRAM save state map, i.e. kvm_smm_changed() needs to be called after state has been loaded and so cannot be done automatically when setting hflags from RSM. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_emulate.h | 1 + arch/x86/kvm/emulate.c | 3 +++ arch/x86/kvm/x86.c | 33 +++++++++++++++------------------ 3 files changed, 19 insertions(+), 18 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h index ec489c432850..feab24cac610 100644 --- a/arch/x86/include/asm/kvm_emulate.h +++ b/arch/x86/include/asm/kvm_emulate.h @@ -228,6 +228,7 @@ struct x86_emulate_ops { void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags); int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, const char *smstate); + void (*post_leave_smm)(struct x86_emulate_ctxt *ctxt); }; diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index ae0d289b50fe..a6b282853253 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2629,6 +2629,9 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt) ctxt->ops->set_hflags(ctxt, ctxt->ops->get_hflags(ctxt) & ~(X86EMUL_SMM_INSIDE_NMI_MASK | X86EMUL_SMM_MASK)); + + ctxt->ops->post_leave_smm(ctxt); + return X86EMUL_CONTINUE; } diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 6ee1f9e5d3fb..472bbbbe153a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3530,7 +3530,7 @@ static void kvm_vcpu_ioctl_x86_get_vcpu_events(struct kvm_vcpu *vcpu, memset(&events->reserved, 0, sizeof(events->reserved)); } -static void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags); +static void kvm_smm_changed(struct kvm_vcpu *vcpu); static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, struct kvm_vcpu_events *events) @@ -3590,12 +3590,13 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu, vcpu->arch.apic->sipi_vector = events->sipi_vector; if (events->flags & KVM_VCPUEVENT_VALID_SMM) { - u32 hflags = vcpu->arch.hflags; - if (events->smi.smm) - hflags |= HF_SMM_MASK; - else - hflags &= ~HF_SMM_MASK; - kvm_set_hflags(vcpu, hflags); + if (!!(vcpu->arch.hflags & HF_SMM_MASK) != events->smi.smm) { + if (events->smi.smm) + vcpu->arch.hflags |= HF_SMM_MASK; + else + vcpu->arch.hflags &= ~HF_SMM_MASK; + kvm_smm_changed(vcpu); + } vcpu->arch.smi_pending = events->smi.pending; @@ -5960,7 +5961,7 @@ static unsigned emulator_get_hflags(struct x86_emulate_ctxt *ctxt) static void emulator_set_hflags(struct x86_emulate_ctxt *ctxt, unsigned emul_flags) { - kvm_set_hflags(emul_to_vcpu(ctxt), emul_flags); + emul_to_vcpu(ctxt)->arch.hflags = emul_flags; } static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, @@ -5969,6 +5970,11 @@ static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, return kvm_x86_ops->pre_leave_smm(emul_to_vcpu(ctxt), smstate); } +static void emulator_post_leave_smm(struct x86_emulate_ctxt *ctxt) +{ + kvm_smm_changed(emul_to_vcpu(ctxt)); +} + static const struct x86_emulate_ops emulate_ops = { .read_gpr = emulator_read_gpr, .write_gpr = emulator_write_gpr, @@ -6009,6 +6015,7 @@ static const struct x86_emulate_ops emulate_ops = { .get_hflags = emulator_get_hflags, .set_hflags = emulator_set_hflags, .pre_leave_smm = emulator_pre_leave_smm, + .post_leave_smm = emulator_post_leave_smm, }; static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask) @@ -6250,16 +6257,6 @@ static void kvm_smm_changed(struct kvm_vcpu *vcpu) kvm_mmu_reset_context(vcpu); } -static void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags) -{ - unsigned changed = vcpu->arch.hflags ^ emul_flags; - - vcpu->arch.hflags = emul_flags; - - if (changed & HF_SMM_MASK) - kvm_smm_changed(vcpu); -} - static int kvm_vcpu_check_hw_bp(unsigned long addr, u32 type, u32 dr7, unsigned long *db) { -- cgit v1.2.3-55-g7522 From b68f3cc7d978943fcf85148165b00594c38db776 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 2 Apr 2019 08:10:48 -0700 Subject: KVM: x86: Always use 32-bit SMRAM save state for 32-bit kernels Invoking the 64-bit variation on a 32-bit kenrel will crash the guest, trigger a WARN, and/or lead to a buffer overrun in the host, e.g. rsm_load_state_64() writes r8-r15 unconditionally, but enum kvm_reg and thus x86_emulate_ctxt._regs only define r8-r15 for CONFIG_X86_64. KVM allows userspace to report long mode support via CPUID, even though the guest is all but guaranteed to crash if it actually tries to enable long mode. But, a pure 32-bit guest that is ignorant of long mode will happily plod along. SMM complicates things as 64-bit CPUs use a different SMRAM save state area. KVM handles this correctly for 64-bit kernels, e.g. uses the legacy save state map if userspace has hid long mode from the guest, but doesn't fare well when userspace reports long mode support on a 32-bit host kernel (32-bit KVM doesn't support 64-bit guests). Since the alternative is to crash the guest, e.g. by not loading state or explicitly requesting shutdown, unconditionally use the legacy SMRAM save state map for 32-bit KVM. If a guest has managed to get far enough to handle SMIs when running under a weird/buggy userspace hypervisor, then don't deliberately crash the guest since there are no downsides (from KVM's perspective) to allow it to continue running. Fixes: 660a5d517aaab ("KVM: x86: save/load state on SMM switch") Cc: stable@vger.kernel.org Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 10 ++++++++++ arch/x86/kvm/x86.c | 10 ++++++---- 2 files changed, 16 insertions(+), 4 deletions(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index f3284827c432..d0d5dd44b4f4 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2331,12 +2331,16 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt) static int emulator_has_longmode(struct x86_emulate_ctxt *ctxt) { +#ifdef CONFIG_X86_64 u32 eax, ebx, ecx, edx; eax = 0x80000001; ecx = 0; ctxt->ops->get_cpuid(ctxt, &eax, &ebx, &ecx, &edx, false); return edx & bit(X86_FEATURE_LM); +#else + return false; +#endif } static void rsm_set_desc_flags(struct desc_struct *desc, u32 flags) @@ -2372,6 +2376,7 @@ static int rsm_load_seg_32(struct x86_emulate_ctxt *ctxt, const char *smstate, return X86EMUL_CONTINUE; } +#ifdef CONFIG_X86_64 static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, const char *smstate, int n) { @@ -2391,6 +2396,7 @@ static int rsm_load_seg_64(struct x86_emulate_ctxt *ctxt, const char *smstate, ctxt->ops->set_segment(ctxt, selector, &desc, base3, n); return X86EMUL_CONTINUE; } +#endif static int rsm_enter_protected_mode(struct x86_emulate_ctxt *ctxt, u64 cr0, u64 cr3, u64 cr4) @@ -2492,6 +2498,7 @@ static int rsm_load_state_32(struct x86_emulate_ctxt *ctxt, return rsm_enter_protected_mode(ctxt, cr0, cr3, cr4); } +#ifdef CONFIG_X86_64 static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, const char *smstate) { @@ -2554,6 +2561,7 @@ static int rsm_load_state_64(struct x86_emulate_ctxt *ctxt, return X86EMUL_CONTINUE; } +#endif static int em_rsm(struct x86_emulate_ctxt *ctxt) { @@ -2621,9 +2629,11 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt) if (ctxt->ops->pre_leave_smm(ctxt, buf)) return X86EMUL_UNHANDLEABLE; +#ifdef CONFIG_X86_64 if (emulator_has_longmode(ctxt)) ret = rsm_load_state_64(ctxt, buf); else +#endif ret = rsm_load_state_32(ctxt, buf); if (ret != X86EMUL_CONTINUE) { diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 472bbbbe153a..f10fef561573 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7441,9 +7441,9 @@ static void enter_smm_save_state_32(struct kvm_vcpu *vcpu, char *buf) put_smstate(u32, buf, 0x7ef8, vcpu->arch.smbase); } +#ifdef CONFIG_X86_64 static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf) { -#ifdef CONFIG_X86_64 struct desc_ptr dt; struct kvm_segment seg; unsigned long val; @@ -7493,10 +7493,8 @@ static void enter_smm_save_state_64(struct kvm_vcpu *vcpu, char *buf) for (i = 0; i < 6; i++) enter_smm_save_seg_64(vcpu, buf, i); -#else - WARN_ON_ONCE(1); -#endif } +#endif static void enter_smm(struct kvm_vcpu *vcpu) { @@ -7507,9 +7505,11 @@ static void enter_smm(struct kvm_vcpu *vcpu) trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, true); memset(buf, 0, 512); +#ifdef CONFIG_X86_64 if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) enter_smm_save_state_64(vcpu, buf); else +#endif enter_smm_save_state_32(vcpu, buf); /* @@ -7567,8 +7567,10 @@ static void enter_smm(struct kvm_vcpu *vcpu) kvm_set_segment(vcpu, &ds, VCPU_SREG_GS); kvm_set_segment(vcpu, &ds, VCPU_SREG_SS); +#ifdef CONFIG_X86_64 if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) kvm_x86_ops->set_efer(vcpu, 0); +#endif kvm_update_cpuid(vcpu); kvm_mmu_reset_context(vcpu); -- cgit v1.2.3-55-g7522 From be43c440eb5d0ccfdb0d67d5a4c9d579ff988b75 Mon Sep 17 00:00:00 2001 From: Hariprasad Kelam Date: Sat, 6 Apr 2019 15:06:58 +0530 Subject: KVM: x86: fix warning Using plain integer as NULL pointer Changed passing argument as "0 to NULL" which resolves below sparse warning arch/x86/kvm/x86.c:3096:61: warning: Using plain integer as NULL pointer Signed-off-by: Hariprasad Kelam Signed-off-by: Paolo Bonzini --- arch/x86/kvm/x86.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/kvm/x86.c') diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index f10fef561573..a0d1fc80ac5a 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3095,7 +3095,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext) break; case KVM_CAP_NESTED_STATE: r = kvm_x86_ops->get_nested_state ? - kvm_x86_ops->get_nested_state(NULL, 0, 0) : 0; + kvm_x86_ops->get_nested_state(NULL, NULL, 0) : 0; break; default: break; -- cgit v1.2.3-55-g7522