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2024-06-17target/i386: convert CMPXCHG to new decoderPaolo Bonzini
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: convert XADD to new decoderPaolo Bonzini
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: convert LZCNT/TZCNT/BSF/BSR/POPCNT to new decoderPaolo Bonzini
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: convert SHLD/SHRD to new decoderPaolo Bonzini
Use the same flag generation code as SHL and SHR, but use the existing gen_shiftd_rm_T1 function to compute the result as well as CC_SRC. Decoding-wise, SHLD/SHRD by immediate count as a 4 operand instruction because s->T0 and s->T1 actually occupy three op slots. The infrastructure used by opcodes in the 0F 3A table works fine. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: adapt gen_shift_count for SHLD/SHRDPaolo Bonzini
SHLD/SHRD can have 3 register operands - s->T0, s->T1 and either 1 or CL - and therefore decode->op[2] is taken by the low part of the register being shifted. Pass X86_OP_* to gen_shift_count from its current callers and hardcode cpu_regs[R_ECX] as the shift count. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: pull load/writeback out of gen_shiftd_rm_T1Paolo Bonzini
Use gen_ld_modrm/gen_st_modrm, moving them and gen_shift_flags to the caller. This way, gen_shiftd_rm_T1 becomes something that the new decoder can call. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: convert non-grouped, helper-based 2-byte opcodesPaolo Bonzini
These have very simple generators and no need for complex group decoding. Apart from LAR/LSL which are simplified to use gen_op_deposit_reg_v and movcond, the code is generally lifted from translate.c into the generators. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: split X86_CHECK_prot into PE and VM86 checksPaolo Bonzini
SYSENTER is allowed in VM86 mode, but not in real mode. Split the check so that PE and !VM86 are covered by separate bits. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: finish converting 0F AE to the new decoderPaolo Bonzini
This is already partly implemented due to VLDMXCSR and VSTMXCSR; finish the job. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: fix bad sorting of entries in the 0F tablePaolo Bonzini
Aesthetic change only. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: replace read_crN helper with read_cr8Paolo Bonzini
All other control registers are stored plainly in CPUX86State. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-17target/i386: convert MOV from/to CR and DR to new decoderPaolo Bonzini
Complete implementation of C and D operand types, then the operations are just MOVs. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: fix processing of intercept 0 (read CR0)Paolo Bonzini
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: replace NoSeg special with NoLoadEAPaolo Bonzini
This is a bit more generic, as it can be applied to MPX as well. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: change X86_ENTRYwr to use T0, use it for movesPaolo Bonzini
Just like X86_ENTRYr, X86_ENTRYwr is easily changed to use only T0. In this case, the motivation is to use it for the MOV instruction family. The case when you need to preserve the input value is the odd one, as it is used basically only for BLS* instructions. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: change X86_ENTRYr to use T0Paolo Bonzini
I am not sure why I made it use T1. It is a bit more symmetric with respect to X86_ENTRYwr (which uses T0 for the "w"ritten operand and T1 for the "r"ead operand), but it is also less flexible because it does not let you apply zextT0/sextT0. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: put BLS* input in T1, use generic flag writebackPaolo Bonzini
This makes for easier cpu_cc_* setup, and not using set_cc_op() should come in handy if QEMU ever implements APX. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: rewrite flags writeback for ADCX/ADOXPaolo Bonzini
Avoid using set_cc_op() in preparation for implementing APX; treat CC_OP_EFLAGS similar to the case where we have the "opposite" cc_op (CC_OP_ADOX for ADCX and CC_OP_ADCX for ADOX), except the resulting cc_op is not CC_OP_ADCOX. This is written easily as two "if"s, whose conditions are both false for CC_OP_EFLAGS, both true for CC_OP_ADCOX, and one each true for CC_OP_ADCX/ADOX. The new logic also makes it easy to drop usage of tmp0. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11target/i386: remove CPUX86State argument from generator functionsPaolo Bonzini
CPUX86State argument would only be used to fetch bytes, but that has to be done before the generator function is called. So remove it, and all temptation together with it. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11i386/sev: Return when sev_common is nullPankaj Gupta
Fixes Coverity CID 1546885. Fixes: 16dcf200dc ("i386/sev: Introduce "sev-common" type to encapsulate common SEV state") Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com> Message-ID: <20240607183611.1111100-4-pankaj.gupta@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11i386/sev: Move SEV_COMMON null check before dereferencingPankaj Gupta
Fixes Coverity CID 1546886. Fixes: 9861405a8f ("i386/sev: Invoke launch_updata_data() for SEV class") Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com> Message-ID: <20240607183611.1111100-3-pankaj.gupta@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11i386/sev: fix unreachable code coverity issuePankaj Gupta
Set 'finish->id_block_en' early, so that it is properly reset. Fixes coverity CID 1546887. Fixes: 7b34df4426 ("i386/sev: Introduce 'sev-snp-guest' object") Signed-off-by: Pankaj Gupta <pankaj.gupta@amd.com> Message-ID: <20240607183611.1111100-2-pankaj.gupta@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-11i386/cpu: fixup number of addressable IDs for processor cores in the ↵Chuang Xu
physical package When QEMU is started with: -cpu host,host-cache-info=on,l3-cache=off \ -smp 2,sockets=1,dies=1,cores=1,threads=2 Guest can't acquire maximum number of addressable IDs for processor cores in the physical package from CPUID[04H]. When creating a CPU topology of 1 core per package, host-cache-info only uses the Host's addressable core IDs field (CPUID.04H.EAX[bits 31-26]), resulting in a conflict (on the multicore Host) between the Guest core topology information in this field and the Guest's actual cores number. Fix it by removing the unnecessary condition to cover 1 core per package case. This is safe because cores_per_pkg will not be 0 and will be at least 1. Fixes: d7caf13b5fcf ("x86: cpu: fixup number of addressable IDs for logical processors sharing cache") Signed-off-by: Guixiong Wei <weiguixiong@bytedance.com> Signed-off-by: Yipeng Yin <yinyipeng@bytedance.com> Signed-off-by: Chuang Xu <xuchuangxclwt@bytedance.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Message-ID: <20240611032314.64076-1-xuchuangxclwt@bytedance.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386: Add support for overflow recoveryJohn Allen
Add cpuid bit definition for overflow recovery. This is needed in the case where a deferred error has been sent to the guest, a guest process accesses the poisoned memory, but the machine_check_poll function has not yet handled the original deferred error. If overflow recovery is not set in this case, when we handle the uncorrected error from the poisoned memory access, the overflow bit will be set and will result in the guest being shut down. By the time the MCE reaches the guest, the overflow has been handled by the host and has not caused a shutdown, so include the bit unconditionally. Signed-off-by: John Allen <john.allen@amd.com> Message-ID: <20240603193622.47156-4-john.allen@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386: Add support for SUCCOR featureJohn Allen
Add cpuid bit definition for the SUCCOR feature. This cpuid bit is required to be exposed to guests to allow them to handle machine check exceptions on AMD hosts. ---- v2: - Add "succor" feature word. - Add case to kvm_arch_get_supported_cpuid for the SUCCOR feature. Reported-by: William Roche <william.roche@oracle.com> Reviewed-by: Joao Martins <joao.m.martins@oracle.com> Signed-off-by: John Allen <john.allen@amd.com> Message-ID: <20240603193622.47156-3-john.allen@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386: Fix MCE support for AMD hostsJohn Allen
For the most part, AMD hosts can use the same MCE injection code as Intel, but there are instances where the qemu implementation is Intel specific. First, MCE delivery works differently on AMD and does not support broadcast. Second, kvm_mce_inject generates MCEs that include a number of Intel specific status bits. Modify kvm_mce_inject to properly generate MCEs on AMD platforms. Reported-by: William Roche <william.roche@oracle.com> Signed-off-by: John Allen <john.allen@amd.com> Message-ID: <20240603193622.47156-2-john.allen@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: Add get/set/migrate support for FRED MSRsXin Li
FRED CPU states are managed in 9 new FRED MSRs, in addtion to a few existing CPU registers and MSRs, e.g., CR4.FRED and MSR_IA32_PL0_SSP. Save/restore/migrate FRED MSRs if FRED is exposed to the guest. Tested-by: Shan Kang <shan.kang@intel.com> Signed-off-by: Xin Li <xin3.li@intel.com> Message-ID: <20231109072012.8078-7-xin3.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: enumerate VMX nested-exception supportXin Li
Allow VMX nested-exception support to be exposed in KVM guests, thus nested KVM guests can enumerate it. Tested-by: Shan Kang <shan.kang@intel.com> Signed-off-by: Xin Li <xin3.li@intel.com> Message-ID: <20231109072012.8078-6-xin3.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: mark CR4.FRED not reservedXin Li
The CR4.FRED bit, i.e., CR4[32], is no longer a reserved bit when FRED is exposed to guests, otherwise it is still a reserved bit. Tested-by: Shan Kang <shan.kang@intel.com> Signed-off-by: Xin Li <xin3.li@intel.com> Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Message-ID: <20231109072012.8078-3-xin3.li@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: add support for FRED in CPUID enumerationXin Li
FRED, i.e., the Intel flexible return and event delivery architecture, defines simple new transitions that change privilege level (ring transitions). The new transitions defined by the FRED architecture are FRED event delivery and, for returning from events, two FRED return instructions. FRED event delivery can effect a transition from ring 3 to ring 0, but it is used also to deliver events incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to ring 3, while the other (ERETS) returns while remaining in ring 0. Collectively, FRED event delivery and the FRED return instructions are FRED transitions. In addition to these transitions, the FRED architecture defines a new instruction (LKGS) for managing the state of the GS segment register. The LKGS instruction can be used by 64-bit operating systems that do not use the new FRED transitions. WRMSRNS is an instruction that behaves exactly like WRMSR, with the only difference being that it is not a serializing instruction by default. Under certain conditions, WRMSRNS may replace WRMSR to improve performance. FRED uses it to switch RSP0 in a faster manner. Search for the latest FRED spec in most search engines with this search pattern: site:intel.com FRED (flexible return and event delivery) specification The CPUID feature flag CPUID.(EAX=7,ECX=1):EAX[17] enumerates FRED, and the CPUID feature flag CPUID.(EAX=7,ECX=1):EAX[18] enumerates LKGS, and the CPUID feature flag CPUID.(EAX=7,ECX=1):EAX[19] enumerates WRMSRNS. Add CPUID definitions for FRED/LKGS/WRMSRNS, and expose them to KVM guests. Because FRED relies on LKGS and WRMSRNS, add that to feature dependency map. Tested-by: Shan Kang <shan.kang@intel.com> Signed-off-by: Xin Li <xin3.li@intel.com> Message-ID: <20231109072012.8078-2-xin3.li@intel.com> [Fix order of dependencies, add dependencies from LM to FRED. - Paolo] Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386/hvf: Updates API usage to use modern vCPU run functionPhil Dennis-Jordan
macOS 10.15 introduced the more efficient hv_vcpu_run_until() function to supersede hv_vcpu_run(). According to the documentation, there is no longer any reason to use the latter on modern host OS versions, especially after 11.0 added support for an indefinite deadline. Observed behaviour of the newer function is that as documented, it exits much less frequently - and most of the original function’s exits seem to have been effectively pointless. Another reason to use the new function is that it is a prerequisite for using newer features such as in-kernel APIC support. (Not covered by this patch.) This change implements the upgrade by selecting one of three code paths at compile time: two static code paths for the new and old functions respectively, when building for targets where the new function is either not available, or where the built executable won’t run on older platforms lacking the new function anyway. The third code path selects dynamically based on runtime detected availability of the weakly-linked symbol. Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu> Message-ID: <20240605112556.43193-7-phil@philjordan.eu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386/hvf: In kick_vcpu use hv_vcpu_interrupt to force exitPhil Dennis-Jordan
When interrupting a vCPU thread, this patch actually tells the hypervisor to stop running guest code on that vCPU. Calling hv_vcpu_interrupt actually forces a vCPU exit, analogously to hv_vcpus_exit on aarch64. Alternatively, if the vCPU thread is not running the VM, it will immediately cause an exit when it attempts to do so. Previously, hvf_kick_vcpu_thread relied upon hv_vcpu_run returning very frequently, including many spurious exits, which made it less of a problem that nothing was actively done to stop the vCPU thread running guest code. The newer, more efficient hv_vcpu_run_until exits much more rarely, so a true "kick" is needed before switching to that. Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu> Message-ID: <20240605112556.43193-6-phil@philjordan.eu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386/hvf: Fixes dirty memory tracking by page granularity RX->RWX changePhil Dennis-Jordan
When using x86 macOS Hypervisor.framework as accelerator, detection of dirty memory regions is implemented by marking logged memory region slots as read-only in the EPT, then setting the dirty flag when a guest write causes a fault. The area marked dirty should then be marked writable in order for subsequent writes to succeed without a VM exit. However, dirty bits are tracked on a per-page basis, whereas the fault handler was marking the whole logged memory region as writable. This change fixes the fault handler so only the protection of the single faulting page is marked as dirty. (Note: the dirty page tracking appeared to work despite this error because HVF’s hv_vcpu_run() function generated unnecessary EPT fault exits, which ended up causing the dirty marking handler to run even when the memory region had been marked RW. When using hv_vcpu_run_until(), a change planned for a subsequent commit, these spurious exits no longer occur, so dirty memory tracking malfunctions.) Additionally, the dirty page is set to permit code execution, the same as all other guest memory; changing memory protection from RX to RW not RWX appears to have been an oversight. Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu> Reviewed-by: Roman Bolshakov <roman@roolebo.dev> Tested-by: Roman Bolshakov <roman@roolebo.dev> Message-ID: <20240605112556.43193-5-phil@philjordan.eu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386/hvf: Fixes some compilation warningsPhil Dennis-Jordan
A bunch of function definitions used empty parentheses instead of (void) syntax, yielding the following warning when building with clang on macOS: warning: a function declaration without a prototype is deprecated in all versions of C [-Wstrict-prototypes] In addition to fixing these function headers, it also fixes what appears to be a typo causing a variable to be unused after initialisation. warning: variable 'entry_ctls' set but not used [-Wunused-but-set-variable] Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu> Reviewed-by: Roman Bolshakov <roman@roolebo.dev> Tested-by: Roman Bolshakov <roman@roolebo.dev> Message-ID: <20240605112556.43193-3-phil@philjordan.eu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08i386/hvf: Adds support for INVTSC cpuid bitPhil Dennis-Jordan
This patch adds the INVTSC bit to the Hypervisor.framework accelerator's CPUID bit passthrough allow-list. Previously, specifying +invtsc in the CPU configuration would fail with the following warning despite the host CPU advertising the feature: qemu-system-x86_64: warning: host doesn't support requested feature: CPUID.80000007H:EDX.invtsc [bit 8] x86 macOS itself relies on a fixed rate TSC for its own Mach absolute time timestamp mechanism, so there's no reason we can't enable this bit for guests. When the feature is enabled, a migration blocker is installed. Signed-off-by: Phil Dennis-Jordan <phil@philjordan.eu> Reviewed-by: Roman Bolshakov <roman@roolebo.dev> Tested-by: Roman Bolshakov <roman@roolebo.dev> Message-ID: <20240605112556.43193-2-phil@philjordan.eu> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix size of EBP writeback in gen_enter()Mark Cave-Ayland
The calculation of FrameTemp is done using the size indicated by mo_pushpop() before being written back to EBP, but the final writeback to EBP is done using the size indicated by mo_stacksize(). In the case where mo_pushpop() is MO_32 and mo_stacksize() is MO_16 then the final writeback to EBP is done using MO_16 which can leave junk in the top 16-bits of EBP after executing ENTER. Change the writeback of EBP to use the same size indicated by mo_pushpop() to ensure that the full value is written back. Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2198 Message-ID: <20240606095319.229650-5-mark.cave-ayland@ilande.co.uk> Cc: qemu-stable@nongnu.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix SP when taking a memory fault during POPMark Cave-Ayland
When OS/2 Warp configures its segment descriptors, many of them are configured with the P flag clear to allow for a fault-on-demand implementation. In the case where the stack value is POPped into the segment registers, the SP is incremented before calling gen_helper_load_seg() to validate the segment descriptor: IN: 0xffef2c0c: 66 07 popl %es OP: ld_i32 loc9,env,$0xfffffffffffffff8 sub_i32 loc9,loc9,$0x1 brcond_i32 loc9,$0x0,lt,$L0 st16_i32 loc9,env,$0xfffffffffffffff8 st8_i32 $0x1,env,$0xfffffffffffffffc ---- 0000000000000c0c 0000000000000000 ext16u_i64 loc0,rsp add_i64 loc0,loc0,ss_base ext32u_i64 loc0,loc0 qemu_ld_a64_i64 loc0,loc0,noat+un+leul,5 add_i64 loc3,rsp,$0x4 deposit_i64 rsp,rsp,loc3,$0x0,$0x10 extrl_i64_i32 loc5,loc0 call load_seg,$0x0,$0,env,$0x0,loc5 add_i64 rip,rip,$0x2 ext16u_i64 rip,rip exit_tb $0x0 set_label $L0 exit_tb $0x7fff58000043 If helper_load_seg() generates a fault when validating the segment descriptor then as the SP has already been incremented, the topmost word of the stack is overwritten by the arguments pushed onto the stack by the CPU before taking the fault handler. As a consequence things rapidly go wrong upon return from the fault handler due to the corrupted stack. Update the logic for the existing writeback condition so that a POP into the segment registers also calls helper_load_seg() first before incrementing the SP, so that if a fault occurs the SP remains unaltered. Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2198 Message-ID: <20240606095319.229650-4-mark.cave-ayland@ilande.co.uk> Fixes: cc1d28bdbe0 ("target/i386: move 00-5F opcodes to new decoder", 2024-05-07) Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: use gen_writeback() within gen_POP()Mark Cave-Ayland
Instead of directly implementing the writeback using gen_op_st_v(), use the existing gen_writeback() function. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Message-ID: <20240606095319.229650-3-mark.cave-ayland@ilande.co.uk> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: use local X86DecodedOp in gen_POP()Mark Cave-Ayland
This will make subsequent changes a little easier to read. Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk> Message-ID: <20240606095319.229650-2-mark.cave-ayland@ilande.co.uk> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: document use of DISAS_NORETURNPaolo Bonzini
DISAS_NORETURN suppresses the work normally done by gen_eob(), and therefore must be used in special cases only. Document them. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: document incorrect semantics of watchpoint following MOV/POP SSPaolo Bonzini
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix TF/RF handling for HLTPaolo Bonzini
HLT uses DISAS_NORETURN because the corresponding helper calls cpu_loop_exit(). However, while gen_eob() clears HF_RF_MASK and synthesizes a #DB exception if single-step is active, none of this is done by HLT. Note that the single-step trap is generated after the halt is finished. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix INHIBIT_IRQ/TF/RF handling for PAUSEPaolo Bonzini
PAUSE uses DISAS_NORETURN because the corresponding helper calls cpu_loop_exit(). However, while HLT clear HF_INHIBIT_IRQ_MASK to correctly handle "STI; HLT", the same is missing from PAUSE. And also gen_eob() clears HF_RF_MASK and synthesizes a #DB exception if single-step is active; none of this is done by HLT and PAUSE. Start fixing PAUSE, HLT will follow. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix INHIBIT_IRQ/TF/RF handling for VMRUNPaolo Bonzini
From vm entry to exit, VMRUN is handled as a single instruction. It uses DISAS_NORETURN in order to avoid processing TF or RF before the first instruction executes in the guest. However, the corresponding handling is missing in vmexit. Add it, and at the same time reorganize the comments with quotes from the manual about the tasks performed by a #VMEXIT. Another gen_eob() task that is missing in VMRUN is preparing the HF_INHIBIT_IRQ flag for the next instruction, in this case by loading it from the VMCB control state. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: disable/enable breakpoints on vmentry/vmexitPaolo Bonzini
If the required DR7 (either from the VMCB or from the host save area) disables a breakpoint that was enabled prior to vmentry or vmexit, it is left enabled and will trigger EXCP_DEBUG. This causes a spurious #DB on the next crossing of the breakpoint. To disable it, vmentry/vmexit must use cpu_x86_update_dr7 to load DR7. Because cpu_x86_update_dr7 takes a 32-bit argument, check reserved bits prior to calling cpu_x86_update_dr7, and do the same for DR6 as well for consistency. This scenario is tested by the "host_rflags" test in kvm-unit-tests. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: implement DR7.GDPaolo Bonzini
DR7.GD triggers a #DB exception on any access to debug registers. The GD bit is cleared so that the #DB handler itself can access the debug registers. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: cleanup PAUSE helpersPaolo Bonzini
Use decode.c's support for intercepts, doing the check in TCG-generated code rather than the helper. This is cleaner because it allows removing the eip_addend argument to helper_pause(), even though it adds a bit of bloat for opcode 0x90's new decoding function. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: cleanup HLT helpersPaolo Bonzini
Use decode.c's support for intercepts, doing the check in TCG-generated code rather than the helper. This is cleaner because it allows removing the eip_addend argument to helper_hlt(). Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix implementation of ICEBPPaolo Bonzini
ICEBP generates a trap-like exception, while gen_exception() produces a fault. Resurrect gen_update_eip_next() to implement the desired semantics. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-06-08target/i386: fix pushed value of EFLAGS.RFPaolo Bonzini
When preparing an exception stack frame for a fault exception, the value pushed for RF is 1. Take that into account. The same should be true of interrupts for repeated string instructions, but the situation there is complicated. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>