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| * KVM: x86: Remove FIXMEs in emulate.c for the function,task_switch_32Nicholas Krause2015-01-08
| | | | | | | | | | | | | | | | | | Remove FIXME comments about needing fault addresses to be returned. These are propaagated from walk_addr_generic to gva_to_gpa and from there to ops->read_std and ops->write_std. Signed-off-by: Nicholas Krause <xerofoify@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: x86: SYSENTER emulation is brokenNadav Amit2015-01-23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SYSENTER emulation is broken in several ways: 1. It misses the case of 16-bit code segments completely (CVE-2015-0239). 2. MSR_IA32_SYSENTER_CS is checked in 64-bit mode incorrectly (bits 0 and 1 can still be set without causing #GP). 3. MSR_IA32_SYSENTER_EIP and MSR_IA32_SYSENTER_ESP are not masked in legacy-mode. 4. There is some unneeded code. Fix it. Cc: stable@vger.linux.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: x86: Fix of previously incomplete fix for CVE-2014-8480Nadav Amit2015-01-23
|/ | | | | | | | | STR and SLDT with rip-relative operand can cause a host kernel oops. Mark them as DstMem as well. Cc: stable@vger.linux.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds2014-12-18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull KVM update from Paolo Bonzini: "3.19 changes for KVM: - spring cleaning: removed support for IA64, and for hardware- assisted virtualization on the PPC970 - ARM, PPC, s390 all had only small fixes For x86: - small performance improvements (though only on weird guests) - usual round of hardware-compliancy fixes from Nadav - APICv fixes - XSAVES support for hosts and guests. XSAVES hosts were broken because the (non-KVM) XSAVES patches inadvertently changed the KVM userspace ABI whenever XSAVES was enabled; hence, this part is going to stable. Guest support is just a matter of exposing the feature and CPUID leaves support" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (179 commits) KVM: move APIC types to arch/x86/ KVM: PPC: Book3S: Enable in-kernel XICS emulation by default KVM: PPC: Book3S HV: Improve H_CONFER implementation KVM: PPC: Book3S HV: Fix endianness of instruction obtained from HEIR register KVM: PPC: Book3S HV: Remove code for PPC970 processors KVM: PPC: Book3S HV: Tracepoints for KVM HV guest interactions KVM: PPC: Book3S HV: Simplify locking around stolen time calculations arch: powerpc: kvm: book3s_paired_singles.c: Remove unused function arch: powerpc: kvm: book3s_pr.c: Remove unused function arch: powerpc: kvm: book3s.c: Remove some unused functions arch: powerpc: kvm: book3s_32_mmu.c: Remove unused function KVM: PPC: Book3S HV: Check wait conditions before sleeping in kvmppc_vcore_blocked KVM: PPC: Book3S HV: ptes are big endian KVM: PPC: Book3S HV: Fix inaccuracies in ICP emulation for H_IPI KVM: PPC: Book3S HV: Fix KSM memory corruption KVM: PPC: Book3S HV: Fix an issue where guest is paused on receiving HMI KVM: PPC: Book3S HV: Fix computation of tlbie operand KVM: PPC: Book3S HV: Add missing HPTE unlock KVM: PPC: BookE: Improve irq inject tracepoint arm/arm64: KVM: Require in-kernel vgic for the arch timers ...
| * KVM: x86: em_ret_far overrides cplNadav Amit2014-12-11
| | | | | | | | | | | | | | | | | | | | commit d50eaa18039b ("KVM: x86: Perform limit checks when assigning EIP") mistakenly used zero as cpl on em_ret_far. Use the actual one. Fixes: d50eaa18039b8b848c2285478d0775335ad5e930 Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulate should check #UD before #GPNadav Amit2014-12-10
| | | | | | | | | | | | | | | | | | | | Intel SDM table 6-2 ("Priority Among Simultaneous Exceptions and Interrupts") shows that faults from decoding the next instruction got higher priority than general protection. Moving the protected-mode check before the CPL check to avoid wrong exception on vm86 mode. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Do not push eflags.vm on pushfNadav Amit2014-12-10
| | | | | | | | | | | | | | | | | | The pushf instruction does not push eflags.VM, so emulation should not do so as well. Although eflags.RF should not be pushed as well, it is already cleared by the time pushf is executed. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Remove prefix flag when GP macro is usedNadav Amit2014-12-10
| | | | | | | | | | | | | | | | The macro GP already sets the flag Prefix. Remove the redundant flag for 0f_38_f0 and 0f_38_f1 opcodes. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Generate #UD when memory operand is requiredNadav Amit2014-12-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Certain x86 instructions that use modrm operands only allow memory operand (i.e., mod012), and cause a #UD exception otherwise. KVM ignores this fact. Currently, the instructions that are such and are emulated by KVM are MOVBE, MOVNTPS, MOVNTPD and MOVNTI. MOVBE is the most blunt example, since it may be emulated by the host regardless of MMIO. The fix introduces a new group for handling such instructions, marking mod3 as illegal instruction. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Remove FIXMEs in emulate.cNicholas Krause2014-11-19
| | | | | | | | | | | | | | | | | | Remove FIXME comments about needing fault addresses to be returned. These are propaagated from walk_addr_generic to gva_to_gpa and from there to ops->read_std and ops->write_std. Signed-off-by: Nicholas Krause <xerofoify@gmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: emulator: remove duplicated limit checkPaolo Bonzini2014-11-19
| | | | | | | | | | | | | | | | The check on the higher limit of the segment, and the check on the maximum accessible size, is the same for both expand-up and expand-down segments. Only the computation of "lim" varies. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: emulator: remove code duplication in register_address{,_increment}Paolo Bonzini2014-11-19
| | | | | | | | | | | | | | | | | | | | | | | | register_address has been a duplicate of address_mask ever since the ancestor of __linearize was born in 90de84f50b42 (KVM: x86 emulator: preserve an operand's segment identity, 2010-11-17). However, we can put it to a better use by including the call to reg_read in register_address. Similarly, the call to reg_rmw can be moved to register_address_increment. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Move __linearize masking of la into switchNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | In __linearize there is check of the condition whether to check if masking of the linear address is needed. It occurs immediately after switch that evaluates the same condition. Merge them. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Non-canonical access using SS should cause #SSNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | When SS is used using a non-canonical address, an #SS exception is generated on real hardware. KVM emulator causes a #GP instead. Fix it to behave as real x86 CPU. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Perform limit checks when assigning EIPNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | If branch (e.g., jmp, ret) causes limit violations, since the target IP > limit, the #GP exception occurs before the branch. In other words, the RIP pushed on the stack should be that of the branch and not that of the target. To do so, we can call __linearize, with new EIP, which also saves us the code which performs the canonical address checks. On the case of assigning an EIP >= 2^32 (when switching cs.l), we also safe, as __linearize will check the new EIP does not exceed the limit and would trigger #GP(0) otherwise. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulator performs privilege checks on __linearizeNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When segment is accessed, real hardware does not perform any privilege level checks. In contrast, KVM emulator does. This causes some discrepencies from real hardware. For instance, reading from readable code segment may fail due to incorrect segment checks. In addition, it introduces unnecassary overhead. To reference Intel SDM 5.5 ("Privilege Levels"): "Privilege levels are checked when the segment selector of a segment descriptor is loaded into a segment register." The SDM never mentions privilege level checks during memory access, except for loading far pointers in section 5.10 ("Pointer Validation"). Those are actually segment selector loads and are emulated in the similarily (i.e., regardless to __linearize checks). This behavior was also checked using sysexit. A data-segment whose DPL=0 was loaded, and after sysexit (CPL=3) it is still accessible. Therefore, all the privilege level checks in __linearize are removed. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Stack size is overridden by __linearizeNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When performing segmented-read/write in the emulator for stack operations, it ignores the stack size, and uses the ad_bytes as indication for the pointer size. As a result, a wrong address may be accessed. To fix this behavior, we can remove the masking of address in __linearize and perform it beforehand. It is already done for the operands (so currently it is inefficiently done twice). It is missing in two cases: 1. When using rip_relative 2. On fetch_bit_operand that changes the address. This patch masks the address on these two occassions, and removes the masking from __linearize. Note that it does not mask EIP during fetch. In protected/legacy mode code fetch when RIP >= 2^32 should result in #GP and not wrap-around. Since we make limit checks within __linearize, this is the expected behavior. Partial revert of commit 518547b32ab4 (KVM: x86: Emulator does not calculate address correctly, 2014-09-30). Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Revert NoBigReal patch in the emulatorNadav Amit2014-11-19
| | | | | | | | | | | | | | | | | | | | | | Commit 10e38fc7cab6 ("KVM: x86: Emulator flag for instruction that only support 16-bit addresses in real mode") introduced NoBigReal for instructions such as MONITOR. Apparetnly, the Intel SDM description that led to this patch is misleading. Since no instruction is using NoBigReal, it is safe to remove it, we fully understand what the SDM means. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: MOVNTI emulation min opsize is not respectedNadav Amit2014-11-08
| | | | | | | | | | | | | | | | | | | | | | | | Commit 3b32004a66e9 ("KVM: x86: movnti minimum op size of 32-bit is not kept") did not fully fix the minimum operand size of MONTI emulation. Still, MOVNTI may be mistakenly performed using 16-bit opsize. This patch add No16 flag to mark an instruction does not support 16-bits operand size. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Return UNHANDLABLE on unsupported SYSENTERNadav Amit2014-11-08
| | | | | | | | | | | | | | | | | | | | Now that KVM injects #UD on "unhandlable" error, it makes better sense to return such error on sysenter instead of directly injecting #UD to the guest. This allows to track more easily the unhandlable cases the emulator does not support. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulator mis-decodes VEX instructions on real-modeNadav Amit2014-11-08
| | | | | | | | | | | | | | | | | | | | | | | | | | Commit 7fe864dc942c (KVM: x86: Mark VEX-prefix instructions emulation as unimplemented, 2014-06-02) marked VEX instructions as such in protected mode. VEX-prefix instructions are not supported relevant on real-mode and VM86, but should cause #UD instead of being decoded as LES/LDS. Fix this behaviour to be consistent with real hardware. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> [Check for mod == 3, rather than 2 or 3. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Remove redundant and incorrect cpl check on task-switchNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Task-switch emulation checks the privilege level prior to performing the task-switch. This check is incorrect in the case of task-gates, in which the tss.dpl is ignored, and can cause superfluous exceptions. Moreover this check is unnecassary, since the CPU checks the privilege levels prior to exiting. Intel SDM 25.4.2 says "If CALL or JMP accesses a TSS descriptor directly outside IA-32e mode, privilege levels are checked on the TSS descriptor" prior to exiting. AMD 15.14.1 says "The intercept is checked before the task switch takes place but after the incoming TSS and task gate (if one was involved) have been checked for correctness." This patch removes the CPL checks for CALL and JMP. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Inject #GP when loading system segments with non-canonical baseNadav Amit2014-11-07
| | | | | | | | | | | | | | | | When emulating LTR/LDTR/LGDT/LIDT, #GP should be injected if the base is non-canonical. Otherwise, VM-entry will fail. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Combine the lgdt and lidt emulation logicNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | LGDT and LIDT emulation logic is almost identical. Merge the logic into a single point to avoid redundancy. This will be used by the next patch that will ensure the bases of the loaded GDTR and IDTR are canonical. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: MOV to CR3 can set bit 63Nadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | Although Intel SDM mentions bit 63 is reserved, MOV to CR3 can have bit 63 set. As Intel SDM states in section 4.10.4 "Invalidation of TLBs and Paging-Structure Caches": " MOV to CR3. ... If CR4.PCIDE = 1 and bit 63 of the instruction’s source operand is 0 ..." In other words, bit 63 is not reserved. KVM emulator currently consider bit 63 as reserved. Fix it. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulate push sreg as done in CoreNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | According to Intel SDM push of segment selectors is done in the following manner: "if the operand size is 32-bits, either a zero-extended value is pushed on the stack or the segment selector is written on the stack using a 16-bit move. For the last case, all recent Core and Atom processors perform a 16-bit move, leaving the upper portion of the stack location unmodified." This patch modifies the behavior to match the core behavior. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Wrong flags on CMPS and SCAS emulationNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CMPS and SCAS instructions are evaluated in the wrong order. For reference (of CMPS), see http://www.fermimn.gov.it/linux/quarta/x86/cmps.htm : "Note that the direction of subtraction for CMPS is [SI] - [DI] or [ESI] - [EDI]. The left operand (SI or ESI) is the source and the right operand (DI or EDI) is the destination. This is the reverse of the usual Intel convention in which the left operand is the destination and the right operand is the source." Introducing em_cmp_r for this matter that performs comparison in reverse order using fastop infrastructure to avoid a wrapper function. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: SYSCALL cannot clear eflags[1]Nadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | SYSCALL emulation currently clears in 64-bit mode eflags according to MSR_SYSCALL_MASK. However, on bare-metal eflags[1] which is fixed to one cannot be cleared, even if MSR_SYSCALL_MASK masks the bit. This wrong behavior may result in failed VM-entry, as VT disallows entry with eflags[1] cleared. This patch sets the bit after masking eflags on syscall. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulation of MOV-sreg to memory uses incorrect sizeNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | | | | | In x86, you can only MOV-sreg to memory with either 16-bits or 64-bits size. In contrast, KVM may write to 32-bits memory on MOV-sreg. This patch fixes KVM behavior, and sets the destination operand size to two, if the destination is memory. When destination is registers, and the operand size is 32-bits, the high 16-bits in modern CPUs is filled with zero. This is handled correctly. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulator should set DR6 upon GD like real CPUNadav Amit2014-11-07
| | | | | | | | | | | | | | It should clear B0-B3 and set BD. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: decode_modrm does not regard modrm correctlyNadav Amit2014-11-07
| | | | | | | | | | | | | | | | | | | | | | In one occassion, decode_modrm uses the rm field after it is extended with REX.B to determine the addressing mode. Doing so causes it not to read the offset for rip-relative addressing with REX.B=1. This patch moves the fetch where we already mask REX.B away instead. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulator performs code segment checks on read accessNadav Amit2014-11-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When read access is performed using a readable code segment, the "conforming" and "non-conforming" checks should not be done. As a result, read using non-conforming readable code segment fails. This is according to Intel SDM 5.6.1 ("Accessing Data in Code Segments"). The fix is not to perform the "non-conforming" checks if the access is not a fetch; the relevant checks are already done when loading the segment. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Reviewed-by: Radim Krčmář <rkrcmar@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Emulator does not calculate address correctlyNadav Amit2014-11-03
| | | | | | | | | | | | | | | | | | | | | | | | | | In long-mode, when the address size is 4 bytes, the linear address is not truncated as the emulator mistakenly does. Instead, the offset within the segment (the ea field) should be truncated according to the address size. As Intel SDM says: "In 64-bit mode, the effective address components are added and the effective address is truncated ... before adding the full 64-bit segment base." Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Sysexit emulation does not mask RIP/RSPNadav Amit2014-11-03
| | | | | | | | | | | | | | | | | | | | If the operand size is not 64-bit, then the sysexit instruction should assign ECX to RSP and EDX to RIP. The current code assigns the full 64-bits. Fix it by masking. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Distinguish between stack operation and near branchesNadav Amit2014-11-03
| | | | | | | | | | | | | | | | | | In 64-bit, stack operations default to 64-bits, but can be overriden (to 16-bit) using opsize override prefix. In contrast, near-branches are always 64-bit. This patch distinguish between the different behaviors. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Getting rid of grp45 in emulatorNadav Amit2014-11-03
| | | | | | | | | | | | | | | | | | Breaking grp45 to the relevant functions to speed up the emulation and simplify the code. In addition, it is necassary the next patch will distinguish between far and near branches according to the flags. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Use new is_noncanonical_address in _linearizeNadav Amit2014-11-03
| | | | | | | | | | | | | | | | Replace the current canonical address check with the new function which is identical. Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: emulator: always inline __linearizePaolo Bonzini2014-11-03
| | | | | | | | | | | | | | The two callers have a lot of constant arguments that can be optimized out. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| * KVM: x86: Fix far-jump to non-canonical checkNadav Amit2014-10-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit d1442d85cc30 ("KVM: x86: Handle errors when RIP is set during far jumps") introduced a bug that caused the fix to be incomplete. Due to incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may not trigger #GP. As we know, this imposes a security problem. In addition, the condition for two warnings was incorrect. Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> [Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: x86: Fix uninitialized op->type for some immediate valuesNadav Amit2014-11-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The emulator could reuse an op->type from a previous instruction for some immediate values. If it mistakenly considers the operands as memory operands, it will performs a memory read and overwrite op->val. Consider for instance the ROR instruction - src2 (the number of times) would be read from memory instead of being used as immediate. Mark every immediate operand as such to avoid this problem. Cc: stable@vger.kernel.org Fixes: c44b4c6ab80eef3a9c52c7b3f0c632942e6489aa Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* | KVM: x86: Fix far-jump to non-canonical checkNadav Amit2014-11-02
|/ | | | | | | | | | | | | | | | Commit d1442d85cc30 ("KVM: x86: Handle errors when RIP is set during far jumps") introduced a bug that caused the fix to be incomplete. Due to incorrect evaluation, far jump to segment with L bit cleared (i.e., 32-bit segment) and RIP with any of the high bits set (i.e, RIP[63:32] != 0) set may not trigger #GP. As we know, this imposes a security problem. In addition, the condition for two warnings was incorrect. Fixes: d1442d85cc30ea75f7d399474ca738e0bc96f715 Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> [Add #ifdef CONFIG_X86_64 to avoid complaints of undefined behavior. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: emulator: fix execution close to the segment limitPaolo Bonzini2014-10-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Emulation of code that is 14 bytes to the segment limit or closer (e.g. RIP = 0xFFFFFFF2 after reset) is broken because we try to read as many as 15 bytes from the beginning of the instruction, and __linearize fails when the passed (address, size) pair reaches out of the segment. To fix this, let __linearize return the maximum accessible size (clamped to 2^32-1) for usage in __do_insn_fetch_bytes, and avoid the limit check by passing zero for the desired size. For expand-down segments, __linearize is performing a redundant check. (u32)(addr.ea + size - 1) <= lim can only happen if addr.ea is close to 4GB; in this case, addr.ea + size - 1 will also fail the check against the upper bound of the segment (which is provided by the D/B bit). After eliminating the redundant check, it is simple to compute the *max_size for expand-down segments too. Now that the limit check is done in __do_insn_fetch_bytes, we want to inject a general protection fault there if size < op_size (like __linearize would have done), instead of just aborting. This fixes booting Tiano Core from emulated flash with EPT disabled. Cc: stable@vger.kernel.org Fixes: 719d5a9b2487e0562f178f61e323c3dc18a8b200 Reported-by: Borislav Petkov <bp@suse.de> Tested-by: Borislav Petkov <bp@suse.de> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: emulator: fix error code for __linearizePaolo Bonzini2014-10-29
| | | | | | | | | | | | | | | | | | | | The error code for #GP and #SS is zero when the segment is used to access an operand or an instruction. It is only non-zero when a segment register is being loaded; for limit checks this means cases such as: * for #GP, when RIP is beyond the limit on a far call (before the first instruction is executed). We do not implement this check, but it would be in em_jmp_far/em_call_far. * for #SS, if the new stack overflows during an inter-privilege-level call to a non-conforming code segment. We do not implement stack switching at all. So use an error code of zero. Reviewed-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: PREFETCH and HINT_NOP should have SrcMem flagNadav Amit2014-10-24
| | | | | | | | | | | | | | | | The decode phase of the x86 emulator assumes that every instruction with the ModRM flag, and which can be used with RIP-relative addressing, has either SrcMem or DstMem. This is not the case for several instructions - prefetch, hint-nop and clflush. Adding SrcMem|NoAccess for prefetch and hint-nop and SrcMem for clflush. This fixes CVE-2014-8480. Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5 Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Emulator does not decode clflush wellNadav Amit2014-10-24
| | | | | | | | | | | | | | | | | Currently, all group15 instructions are decoded as clflush (e.g., mfence, xsave). In addition, the clflush instruction requires no prefix (66/f2/f3) would exist. If prefix exists it may encode a different instruction (e.g., clflushopt). Creating a group for clflush, and different group for each prefix. This has been the case forever, but the next patch needs the cflush group in order to fix a bug introduced in 3.17. Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5 Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: emulate: avoid accessing NULL ctxt->memoppPaolo Bonzini2014-10-24
| | | | | | | | | | | | | A failure to decode the instruction can cause a NULL pointer access. This is fixed simply by moving the "done" label as close as possible to the return. This fixes CVE-2014-8481. Reported-by: Andy Lutomirski <luto@amacapital.net> Cc: stable@vger.kernel.org Fixes: 41061cdb98a0bec464278b4db8e894a3121671f5 Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Decoding guest instructions which cross page boundary may failNadav Amit2014-10-24
| | | | | | | | | | | | Once an instruction crosses a page boundary, the size read from the second page disregards the common case that part of the operand resides on the first page. As a result, fetch of long insturctions may fail, and thereby cause the decoding to fail as well. Cc: stable@vger.kernel.org Fixes: 5cfc7e0f5e5e1adf998df94f8e36edaf5d30d38e Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Handle errors when RIP is set during far jumpsNadav Amit2014-10-24
| | | | | | | | | | | | | | | Far jmp/call/ret may fault while loading a new RIP. Currently KVM does not handle this case, and may result in failed vm-entry once the assignment is done. The tricky part of doing so is that loading the new CS affects the VMCS/VMCB state, so if we fail during loading the new RIP, we are left in unconsistent state. Therefore, this patch saves on 64-bit the old CS descriptor and restores it if loading RIP failed. This fixes CVE-2014-3647. Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Emulator fixes for eip canonical checks on near branchesNadav Amit2014-10-24
| | | | | | | | | | | | | | | | | | Before changing rip (during jmp, call, ret, etc.) the target should be asserted to be canonical one, as real CPUs do. During sysret, both target rsp and rip should be canonical. If any of these values is noncanonical, a #GP exception should occur. The exception to this rule are syscall and sysenter instructions in which the assigned rip is checked during the assignment to the relevant MSRs. This patch fixes the emulator to behave as real CPUs do for near branches. Far branches are handled by the next patch. This fixes CVE-2014-3647. Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* KVM: x86: Fix wrong masking on relative jump/callNadav Amit2014-10-24
| | | | | | | | | | | Relative jumps and calls do the masking according to the operand size, and not according to the address size as the KVM emulator does today. This patch fixes KVM behavior. Cc: stable@vger.kernel.org Signed-off-by: Nadav Amit <namit@cs.technion.ac.il> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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