Commit Graph

375 Commits

Author SHA1 Message Date
Paolo Bonzini
b5a9de3259 target/i386: leave the A20 bit set in the final NPT walk
The A20 mask is only applied to the final memory access.  Nested
page tables are always walked with the raw guest-physical address.

Unlike the previous patch, in this one the masking must be kept, but
it was done too early.

Cc: qemu-stable@nongnu.org
Fixes: 4a1e9d4d11 ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
a28fe7dc19 target/i386: remove unnecessary/wrong application of the A20 mask
If ptw_translate() does a MMU_PHYS_IDX access, the A20 mask is already
applied in get_physical_address(), which is called via probe_access_full()
and x86_cpu_tlb_fill().

If ptw_translate() on the other hand does a MMU_NESTED_IDX access,
the A20 mask must not be applied to the address that is looked up in
the nested page tables; it must be applied only to the addresses that
hold the NPT entries (which is achieved via MMU_PHYS_IDX, per the
previous paragraph).

Therefore, we can remove A20 masking from the computation of the page
table entry's address, and let get_physical_address() or mmu_translate()
apply it when they know they are returning a host-physical address.

Cc: qemu-stable@nongnu.org
Fixes: 4a1e9d4d11 ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
b1661801c1 target/i386: Fix physical address truncation
The address translation logic in get_physical_address() will currently
truncate physical addresses to 32 bits unless long mode is enabled.
This is incorrect when using physical address extensions (PAE) outside
of long mode, with the result that a 32-bit operating system using PAE
to access memory above 4G will experience undefined behaviour.

The truncation code was originally introduced in commit 33dfdb5 ("x86:
only allow real mode to access 32bit without LMA"), where it applied
only to translations performed while paging is disabled (and so cannot
affect guests using PAE).

Commit 9828198 ("target/i386: Add MMU_PHYS_IDX and MMU_NESTED_IDX")
rearranged the code such that the truncation also applied to the use
of MMU_PHYS_IDX and MMU_NESTED_IDX.  Commit 4a1e9d4 ("target/i386: Use
atomic operations for pte updates") brought this truncation into scope
for page table entry accesses, and is the first commit for which a
Windows 10 32-bit guest will reliably fail to boot if memory above 4G
is present.

The truncation code however is not completely redundant.  Even though the
maximum address size for any executed instruction is 32 bits, helpers for
operations such as BOUND, FSAVE or XSAVE may ask get_physical_address()
to translate an address outside of the 32-bit range, if invoked with an
argument that is close to the 4G boundary.  Likewise for processor
accesses, for example TSS or IDT accesses, when EFER.LMA==0.

So, move the address truncation in get_physical_address() so that it
applies to 32-bit MMU indexes, but not to MMU_PHYS_IDX and MMU_NESTED_IDX.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2040
Fixes: 4a1e9d4d11 ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Cc: qemu-stable@nongnu.org
Co-developed-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
90f641531c target/i386: use separate MMU indexes for 32-bit accesses
Accesses from a 32-bit environment (32-bit code segment for instruction
accesses, EFER.LMA==0 for processor accesses) have to mask away the
upper 32 bits of the address.  While a bit wasteful, the easiest way
to do so is to use separate MMU indexes.  These days, QEMU anyway is
compiled with a fixed value for NB_MMU_MODES.  Split MMU_USER_IDX,
MMU_KSMAP_IDX and MMU_KNOSMAP_IDX in two.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
5f97afe254 target/i386: introduce function to query MMU indices
Remove knowledge of specific MMU indexes (other than MMU_NESTED_IDX and
MMU_PHYS_IDX) from mmu_translate().  This will make it possible to split
32-bit and 64-bit MMU indexes.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
d09c79010f target/i386: check validity of VMCB addresses
MSR_VM_HSAVE_PA bits 0-11 are reserved, as are the bits above the
maximum physical address width of the processor.  Setting them to
1 causes a #GP (see "15.30.4 VM_HSAVE_PA MSR" in the AMD manual).

The same is true of VMCB addresses passed to VMRUN/VMLOAD/VMSAVE,
even though the manual is not clear on that.

Cc: qemu-stable@nongnu.org
Fixes: 4a1e9d4d11 ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:39 +01:00
Paolo Bonzini
68fb78d7d5 target/i386: mask high bits of CR3 in 32-bit mode
CR3 bits 63:32 are ignored in 32-bit mode (either legacy 2-level
paging or PAE paging).  Do this in mmu_translate() to remove
the last where get_physical_address() meaningfully drops the high
bits of the address.

Cc: qemu-stable@nongnu.org
Suggested-by: Richard Henderson <richard.henderson@linaro.org>
Fixes: 4a1e9d4d11 ("target/i386: Use atomic operations for pte updates", 2022-10-18)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-28 00:23:38 +01:00
Ziqiao Kong
99d0dcd7f1 target/i386: Generate an illegal opcode exception on cmp instructions with lock prefix
target/i386: As specified by Intel Manual Vol2 3-180, cmp instructions
are not allowed to have lock prefix and a `UD` should be raised. Without
this patch, s1->T0 will be uninitialized and used in the case OP_CMPL.

Signed-off-by: Ziqiao Kong <ziqiaokong@gmail.com>
Message-ID: <20240215095015.570748-2-ziqiaokong@gmail.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-02-16 13:56:09 +01:00
Bui Quang Minh
774204cf98 apic, i386/tcg: add x2apic transitions
This commit adds support for x2APIC transitions when writing to
MSR_IA32_APICBASE register and finally adds CPUID_EXT_X2APIC to
TCG_EXT_FEATURES.

The set_base in APICCommonClass now returns an integer to indicate error in
execution. apic_set_base return -1 on invalid APIC state transition,
accelerator can use this to raise appropriate exception.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Message-Id: <20240111154404.5333-4-minhquangbui99@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-02-14 06:09:32 -05:00
Bui Quang Minh
b2101358e5 i386/tcg: implement x2APIC registers MSR access
This commit creates apic_register_read/write which are used by both
apic_mem_read/write for MMIO access and apic_msr_read/write for MSR access.

The apic_msr_read/write returns -1 on error, accelerator can use this to
raise the appropriate exception.

Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Message-Id: <20240111154404.5333-2-minhquangbui99@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2024-02-14 06:09:32 -05:00
Richard Henderson
3b91614004 include/exec: Change cpu_mmu_index argument to CPUState
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-02-03 16:46:10 +10:00
Philippe Mathieu-Daudé
ec1d32af12 target/i386: Extract x86_cpu_exec_halt() from accel/tcg/
Move this x86-specific code out of the generic accel/tcg/.

Reported-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240124101639.30056-10-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-01-29 21:04:10 +10:00
Philippe Mathieu-Daudé
6ae754815f target/i386: Extract x86_need_replay_interrupt() from accel/tcg/
Move this x86-specific code out of the generic accel/tcg/.

Reviewed-by: Anton Johansson <anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20240124101639.30056-8-philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-01-29 21:04:10 +10:00
Richard Henderson
1764ad70ce include/qemu: Add TCGCPUOps typedef to typedefs.h
QEMU coding style recommends using structure typedefs.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-01-29 21:04:10 +10:00
Anton Johansson
32f0c394bb target: Use vaddr in gen_intermediate_code
Makes gen_intermediate_code() signature target agnostic so the function
can be called from accel/tcg/translate-all.c without target specifics.

Signed-off-by: Anton Johansson <anjo@rev.ng>
Message-Id: <20240119144024.14289-9-anjo@rev.ng>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2024-01-29 07:06:03 +10:00
Peter Maydell
3f2a357b95 HW core patch queue
. Deprecate unmaintained SH-4 models (Samuel)
 . HPET: Convert DPRINTF calls to trace events (Daniel)
 . Implement buffered block writes in Intel PFlash (Gerd)
 . Ignore ELF loadable segments with zero size (Bin)
 . ESP/NCR53C9x: PCI DMA fixes (Mark)
 . PIIX: Simplify Xen PCI IRQ routing (Bernhard)
 . Restrict CPU 'start-powered-off' property to sysemu (Phil)
 
 . target/alpha: Only build sys_helper.c on system emulation (Phil)
 . target/xtensa: Use generic instruction breakpoint API & add test (Max)
 . Restrict icount to system emulation (Phil)
 . Do not set CPUState TCG-specific flags in non-TCG accels (Phil)
 . Cleanup TCG tb_invalidate API (Phil)
 . Correct LoongArch/KVM include path (Bibo)
 . Do not ignore throttle errors in crypto backends (Phil)
 
 . MAINTAINERS updates (Raphael, Zhao)
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Merge tag 'hw-cpus-20240119' of https://github.com/philmd/qemu into staging

HW core patch queue

. Deprecate unmaintained SH-4 models (Samuel)
. HPET: Convert DPRINTF calls to trace events (Daniel)
. Implement buffered block writes in Intel PFlash (Gerd)
. Ignore ELF loadable segments with zero size (Bin)
. ESP/NCR53C9x: PCI DMA fixes (Mark)
. PIIX: Simplify Xen PCI IRQ routing (Bernhard)
. Restrict CPU 'start-powered-off' property to sysemu (Phil)

. target/alpha: Only build sys_helper.c on system emulation (Phil)
. target/xtensa: Use generic instruction breakpoint API & add test (Max)
. Restrict icount to system emulation (Phil)
. Do not set CPUState TCG-specific flags in non-TCG accels (Phil)
. Cleanup TCG tb_invalidate API (Phil)
. Correct LoongArch/KVM include path (Bibo)
. Do not ignore throttle errors in crypto backends (Phil)

. MAINTAINERS updates (Raphael, Zhao)

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# gpg: Signature made Fri 19 Jan 2024 11:32:09 GMT
# gpg:                using RSA key FAABE75E12917221DCFD6BB2E3E32C2CDEADC0DE
# gpg: Good signature from "Philippe Mathieu-Daudé (F4BUG) <f4bug@amsat.org>" [full]
# Primary key fingerprint: FAAB E75E 1291 7221 DCFD  6BB2 E3E3 2C2C DEAD C0DE

* tag 'hw-cpus-20240119' of https://github.com/philmd/qemu: (36 commits)
  configure: Add linux header compile support for LoongArch
  MAINTAINERS: Update hw/core/cpu.c entry
  MAINTAINERS: Update Raphael Norwitz email
  hw/elf_ops: Ignore loadable segments with zero size
  hw/scsi/esp-pci: set DMA_STAT_BCMBLT when BLAST command issued
  hw/scsi/esp-pci: synchronise setting of DMA_STAT_DONE with ESP completion interrupt
  hw/scsi/esp-pci: generate PCI interrupt from separate ESP and PCI sources
  hw/scsi/esp-pci: use correct address register for PCI DMA transfers
  target/riscv: Rename tcg_cpu_FOO() to include 'riscv'
  target/i386: Rename tcg_cpu_FOO() to include 'x86'
  hw/s390x: Rename cpu_class_init() to include 'sclp'
  hw/core/cpu: Rename cpu_class_init() to include 'common'
  accel: Rename accel_init_ops_interfaces() to include 'system'
  cpus: Restrict 'start-powered-off' property to system emulation
  system/watchpoint: Move TCG specific code to accel/tcg/
  system/replay: Restrict icount to system emulation
  hw/pflash: implement update buffer for block writes
  hw/pflash: use ldn_{be,le}_p and stn_{be,le}_p
  hw/pflash: refactor pflash_data_write()
  hw/i386/pc_piix: Make piix_intx_routing_notifier_xen() more device independent
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2024-01-19 11:39:38 +00:00
Philippe Mathieu-Daudé
e129593f6f target/i386: Rename tcg_cpu_FOO() to include 'x86'
The tcg_cpu_FOO() names are x86 specific, so rename
them as x86_tcg_cpu_FOO() (as other names in this file)
to ease navigating the code.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Michael Tokarev <mjt@tls.msk.ru>
Message-ID: <20240111120221.35072-5-philmd@linaro.org>
2024-01-19 12:28:59 +01:00
Paolo Bonzini
729ba8e933 target/i386: pcrel: store low bits of physical address in data[0]
For PC-relative translation blocks, env->eip changes during the
execution of a translation block, Therefore, QEMU must be able to
recover an instruction's PC just from the TranslationBlock struct and
the instruction data with.  Because a TB will not span two pages, QEMU
stores all the low bits of EIP in the instruction data and replaces them
in x86_restore_state_to_opc.  Bits 12 and higher (which may vary between
executions of a PCREL TB, since these only use the physical address in
the hash key) are kept unmodified from env->eip.  The assumption is that
these bits of EIP, unlike bits 0-11, will not change as the translation
block executes.

Unfortunately, this is incorrect when the CS base is not aligned to a page.
Then the linear address of the instructions (i.e. the one with the
CS base addred) indeed will never span two pages, but bits 12+ of EIP
can actually change.  For example, if CS base is 0x80262200 and EIP =
0x6FF4, the first instruction in the translation block will be at linear
address 0x802691F4.  Even a very small TB will cross to EIP = 0x7xxx,
while the linear addresses will remain comfortably within a single page.

The fix is simply to use the low bits of the linear address for data[0],
since those don't change.  Then x86_restore_state_to_opc uses tb->cs_base
to compute a temporary linear address (referring to some unknown
instruction in the TB, but with the correct values of bits 12 and higher);
the low bits are replaced with data[0], and EIP is obtained by subtracting
again the CS base.

Huge thanks to Mark Cave-Ayland for the image and initial debugging,
and to Gitlab user @kjliew for help with bisecting another occurrence
of (hopefully!) the same bug.

It should be relatively easy to write a testcase that performs MMIO on
an EIP with different bits 12+ than the first instruction of the translation
block; any help is welcome.

Fixes: e3a79e0e87 ("target/i386: Enable TARGET_TB_PCREL", 2022-10-11)
Cc: qemu-stable@nongnu.org
Cc: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Cc: Richard Henderson <richard.henderson@linaro.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1759
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1964
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2012
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-01-18 10:43:42 +01:00
guoguangyao
2926eab896 target/i386: fix incorrect EIP in PC-relative translation blocks
The PCREL patches introduced a bug when updating EIP in the !CF_PCREL case.
Using s->pc in func gen_update_eip_next() solves the problem.

Cc: qemu-stable@nongnu.org
Fixes: b5e0d5d22f ("target/i386: Fix 32-bit wrapping of pc/eip computation")
Signed-off-by: guoguangyao <guoguangyao18@mails.ucas.ac.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240115020804.30272-1-guoguangyao18@mails.ucas.ac.cn>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-01-18 10:43:14 +01:00
Richard Henderson
a58506b748 target/i386: Do not re-compute new pc with CF_PCREL
With PCREL, we have a page-relative view of EIP, and an
approximation of PC = EIP+CSBASE that is good enough to
detect page crossings.  If we try to recompute PC after
masking EIP, we will mess up that approximation and write
a corrupt value to EIP.

We already handled masking properly for PCREL, so the
fix in b5e0d5d2 was only needed for the !PCREL path.

Cc: qemu-stable@nongnu.org
Fixes: b5e0d5d22f ("target/i386: Fix 32-bit wrapping of pc/eip computation")
Reported-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20240101230617.129349-1-richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-01-18 10:43:14 +01:00
Stefan Hajnoczi
195801d700 system/cpus: rename qemu_mutex_lock_iothread() to bql_lock()
The Big QEMU Lock (BQL) has many names and they are confusing. The
actual QemuMutex variable is called qemu_global_mutex but it's commonly
referred to as the BQL in discussions and some code comments. The
locking APIs, however, are called qemu_mutex_lock_iothread() and
qemu_mutex_unlock_iothread().

The "iothread" name is historic and comes from when the main thread was
split into into KVM vcpu threads and the "iothread" (now called the main
loop thread). I have contributed to the confusion myself by introducing
a separate --object iothread, a separate concept unrelated to the BQL.

The "iothread" name is no longer appropriate for the BQL. Rename the
locking APIs to:
- void bql_lock(void)
- void bql_unlock(void)
- bool bql_locked(void)

There are more APIs with "iothread" in their names. Subsequent patches
will rename them. There are also comments and documentation that will be
updated in later patches.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Acked-by: Fabiano Rosas <farosas@suse.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Peter Xu <peterx@redhat.com>
Acked-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Acked-by: Hyman Huang <yong.huang@smartx.com>
Reviewed-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Message-id: 20240102153529.486531-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2024-01-08 10:45:43 -05:00
Paolo Bonzini
405c7c0708 target/i386: implement CMPccXADD
The main difficulty here is that a page fault when writing to the destination
must not overwrite the flags.  Therefore, the flags computation must be
inlined instead of using gen_jcc1*.

For simplicity, I am using an unconditional cmpxchg operation, that becomes
a NOP if the comparison fails.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:04:40 +01:00
Paolo Bonzini
e7bbb7cb71 target/i386: introduce flags writeback mechanism
ALU instructions can write to both memory and flags.  If the CC_SRC*
and CC_DST locations have been written already when a memory access
causes a fault, the value in CC_SRC* and CC_DST might be interpreted
with the wrong CC_OP (the one that is in effect before the instruction.

Besides just using the wrong result for the flags, something like
subtracting -1 can have disastrous effects if the current CC_OP is
CC_OP_EFLAGS: this is because QEMU does not expect bits outside the ALU
flags to be set in CC_SRC, and env->eflags can end up set to all-ones.
In the case of the attached testcase, this sets IOPL to 3 and would
cause an assertion failure if SUB is moved to the new decoder.

This mechanism is not really needed for BMI instructions, which can
only write to a register, but put it to use anyway for cleanliness.
In the case of BZHI, the code has to be modified slightly to ensure
that decode->cc_src is written, otherwise the new assertions trigger.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:04:30 +01:00
Paolo Bonzini
4b2baf4a55 target/i386: adjust decoding of J operand
gen_jcc() has been changed to accept a relative offset since the
new decoder was written.  Adjust the J operand, which is meant
to be used with jump instructions such as gen_jcc(), to not
include the program counter and to not truncate the result, as
both operations are now performed by common code.

The result is that J is now the same as the I operand.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:04:30 +01:00
Paolo Bonzini
d4f611711a target/i386: move operand load and writeback out of gen_cmovcc1
Similar to gen_setcc1, make gen_cmovcc1 receive TCGv.  This is more friendly
to simultaneous implementation in the old and the new decoder.

A small wart is that s->T0 of CMOV is currently the *second* argument (which
would ordinarily be in T1).  Therefore, the condition has to be inverted in
order to overwrite s->T0 with cpu_regs[reg] if the MOV is not performed.

This only applies to the old decoder, and this code will go away soon.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:04:15 +01:00
Paolo Bonzini
3497f1646f target/i386: prepare for implementation of STOS/SCAS in new decoder
Do not use gen_op, and pull the load from the accumulator into
disas_insn.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:59 +01:00
Paolo Bonzini
9a5922d6bd target/i386: do not use s->tmp0 for jumps on ECX ==/!= 0
Create a new temporary, to ease the register allocator's work.

Creation of the temporary is pushed into gen_ext_tl, which
also allows NULL as the first parameter now.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:55 +01:00
Paolo Bonzini
1ec46bf237 target/i386: do not use s->tmp4 for push
Just create a temporary for the occasion.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:53 +01:00
Paolo Bonzini
80e55f54ac target/i386: split eflags computation out of gen_compute_eflags
The new x86 decoder wants the gen_* functions to compute EFLAGS before
writeback, which can be an issue for instructions with a memory
destination such as ARPL or shifts.

Extract code to compute the EFLAGS without clobbering CC_SRC, in case
the memory write causes a fault.  The flags writeback mechanism will
take care of copying the result to CC_SRC.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:50 +01:00
Paolo Bonzini
c0099cd40e target/i386: do not clobber T0 on string operations
The new decoder would rather have the operand in T0 when expanding SCAS, rather
than use R_EAX directly as gen_scas currently does.  This makes SCAS more similar
to CMP and SUB, in that CC_DST = T0 - T1.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:24 +01:00
Paolo Bonzini
24c0573bb0 target/i386: do not clobber A0 in POP translation
The new decoder likes to compute the address in A0 very early, so the
gen_lea_v_seg in gen_pop_T0 would clobber the address of the memory
operand.  Instead use T0 since it is already available and will be
overwritten immediately after.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:21 +01:00
Paolo Bonzini
a71e0b246a target/i386: do not decode string source/destination into decode->mem
decode->mem is only used if one operand has has_ea == true.  String
operations will not use decode->mem and will load A0 on their own, because
they are the only case of two memory operands in a single instruction.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:18 +01:00
Paolo Bonzini
8a36bbcf6c target/i386: add X86_SPECIALs for MOVSX and MOVZX
Usually the registers are just moved into s->T0 without much care for
their operand size.  However, in some cases we can get more efficient
code if the operand fetching logic syncs with the emission function
on what is nicer.

All the current uses are mostly demonstrative and only reduce the code
in the emission functions, because the instructions do not support
memory operands.  However the logic is generic and applies to several
more instructions such as MOVSXD (aka movslq), one-byte shift
instructions, multiplications, XLAT, and indirect calls/jumps.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:15 +01:00
Paolo Bonzini
5baf5641cc target/i386: rename zext0/zext2 and make them closer to the manual
X86_SPECIAL_ZExtOp0 and X86_SPECIAL_ZExtOp2 are poorly named; they are a hack
that is needed by scalar insertion and extraction instructions, and not really
related to zero extension: for PEXTR the zero extension is done by the generation
functions, for PINSR the high bits are not used at all and in fact are *not*
filled with zeroes when loaded into s->T1.

Rename the values to match the effect described in the manual, and explain
better in the comments.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:11 +01:00
Paolo Bonzini
6dd2afed55 target/i386: avoid trunc and ext for MULX and RORX
Use _tl operations for 32-bit operands on 32-bit targets, and only go
through trunc and extu ops for 64-bit targets.  While the trunc/ext
ops should be pretty much free after optimization, the optimizer also
does not like having the same temporary used in multiple EBBs.
Therefore it is nicer to not use tmpN* unless necessary.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:08 +01:00
Paolo Bonzini
b609db9477 target/i386: reimplement check for validity of LOCK prefix
The previous check erroneously allowed CMP to be modified with LOCK.
Instead, tag explicitly the instructions that do support LOCK.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:08 +01:00
Paolo Bonzini
8147df44da target/i386: document more deviations from the manual
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:05 +01:00
Paolo Bonzini
2455e9cf5a target/i386: clean up cpu_cc_compute_all
cpu_cc_compute_all() has an argument that is always equal to CC_OP for historical
reasons (dating back to commit a7812ae412, "TCG variable type checking.", 2008-11-17,
which added the argument to helper_cc_compute_all).  It does not make sense for the
argument to have any other value, so remove it and clean up some lines that are not
too long anymore.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:03:02 +01:00
Paolo Bonzini
8cc746525c target/i386: remove unnecessary truncations
gen_lea_v_seg (called by gen_add_A0_ds_seg) already zeroes any
bits of s->A0 beyond s->aflag.  It does so before summing the
segment base and, if not in 64-bit mode, also after summing it.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:02:58 +01:00
Paolo Bonzini
83280f6a62 target/i386: remove unnecessary arguments from raise_interrupt
is_int is always 1, and error_code is always zero.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:02:55 +01:00
Paolo Bonzini
1e7dde8008 target/i386: speedup JO/SETO after MUL or IMUL
OF is equal to the carry flag, so use the same CCPrepare.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:02:52 +01:00
Paolo Bonzini
6032627f07 target/i386: optimize computation of JL and JLE from flags
Take advantage of the fact that there can be no 1 bits between SF and OF.
If they were adjacent, you could sum SF and get a carry only if SF was
already set.  Then the value of OF in the sum is the XOR of OF itself,
the carry (which is SF) and 0 (the value of the OF bit in the addend):
this is OF^SF exactly.

Because OF and SF are not adjacent, just place more 1 bits to the
left so that the carry propagates, which means summing CC_O - CC_S.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-12-29 22:02:48 +01:00
Richard Henderson
b5e0d5d22f target/i386: Fix 32-bit wrapping of pc/eip computation
In 32-bit mode, pc = eip + cs_base is also 32-bit, and must wrap.
Failure to do so results in incorrect memory exceptions to the guest.
Before 732d548732, this was implicitly done via truncation to
target_ulong but only in qemu-system-i386, not qemu-system-x86_64.

To fix this, we must add conditional zero-extensions.
Since we have to test for 32 vs 64-bit anyway, note that cs_base
is always zero in 64-bit mode.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2022
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20231212172510.103305-1-richard.henderson@linaro.org>
2023-12-12 13:35:08 -08:00
Paolo Bonzini
e000687f12 target/i386: validate VEX.W for AVX instructions
Instructions in VEX exception class 6 generally look at the value of
VEX.W.  Note that the manual places some instructions incorrectly in
class 4, for example VPERMQ which has no non-VEX encoding and no legacy
SSE analogue.  AMD does a mess of its own, as documented in the comment
that this patch adds.

Most of them are checked for VEX.W=0, and are listed in the manual
(though with an omission) in table 2-16; VPERMQ and VPERMPD check for
VEX.W=1, which is only listed in the instruction description.  Others,
such as VPSRLV, VPSLLV and the FMA3 instructions, use VEX.W to switch
between a 32-bit and 64-bit operation.

Fix more of the class 4/class 6 mismatches, and implement the check for
VEX.W in TCG.

Acked-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-25 17:35:07 +02:00
Paolo Bonzini
183e6679e3 target/i386: group common checks in the decoding phase
In preparation for adding more similar checks, move the VEX.L=0 check
and several X86_SPECIAL_* checks to a new field, where each bit represent
a common check on unused bits, or a restriction on the processor mode.

Likewise, many SVM intercepts can be checked during the decoding phase,
the main exception being the selective CR0 write, MSR and IOIO intercepts.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-25 17:35:07 +02:00
Paolo Bonzini
e582b629f0 target/i386: implement SHA instructions
The implementation was validated with OpenSSL and with the test vectors in
https://github.com/rust-lang/stdarch/blob/master/crates/core_arch/src/x86/sha.rs.

The instructions provide a ~25% improvement on hashing a 64 MiB file:
runtime goes down from 1.8 seconds to 1.4 seconds; instruction count on
the host goes down from 5.8 billion to 4.8 billion with slightly better
IPC too.  Good job Intel. ;)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-25 17:35:07 +02:00
Richard Henderson
23f3d586e4 target/i386: Use tcg_gen_ext_tl
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-10-22 16:43:31 -07:00
Richard Henderson
46c684c862 target/i386: Use i128 for 128 and 256-bit loads and stores
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2023-10-22 16:32:28 -07:00
Paolo Bonzini
24b34590d0 target/i386: check intercept for XSETBV
Note that this intercept is special; it is checked before the #GP
exception.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2023-10-17 15:20:53 +02:00
Paolo Bonzini
c35b2fb1fd target/i386: fix shadowed variable pasto
Commit a908985971 ("target/i386/seg_helper: introduce tss_set_busy",
2023-09-26) failed to use the tss_selector argument of the new function,
which was therefore unused.

This shows up as a #GP fault when booting old versions of 32-bit
Linux.

Fixes: a908985971 ("target/i386/seg_helper: introduce tss_set_busy", 2023-09-26)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20231011135350.438492-1-pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
2023-10-12 16:37:31 +02:00