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>
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>
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>
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>
The processor tracing features in cpu_x86_cpuid() are hardcoded to a set
that should be safe on all processor that support PT virtualization.
But as an additional check, x86_cpu_filter_features() also checks
that the accelerator supports that safe subset, and if not it marks
CPUID_7_0_EBX_INTEL_PT as unavailable.
This check fails on accelerators other than KVM, but it is actually
unnecessary to do it because KVM is the only accelerator that uses the
safe subset. Everything else just provides nonzero values for CPUID
leaf 0x14 (TCG/HVF because processor tracing is not supported; qtest
because nothing is able to read CPUID anyway). Restricting the check
to KVM fixes a warning with the qtest accelerator:
$ qemu-system-x86_64 -display none -cpu max,mmx=off -accel qtest
qemu-system-x86_64: warning: TCG doesn't support requested feature: CPUID.07H:EBX.intel-pt [bit 25]
The warning also happens in the test-x86-cpuid-compat qtest.
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2096
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240221162910.101327-1-pbonzini@redhat.com>
Fixes: d047402436 ("target/i386: Call accel-agnostic x86_cpu_get_supported_cpuid()")
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
CPUID leaf 7 was grouped together with SGX leaf 0x12 by commit
b9edbadefb ("i386: Propagate SGX CPUID sub-leafs to KVM") by mistake.
SGX leaf 0x12 has its specific logic to check if subleaf (starting from 2)
is valid or not by checking the bit 0:3 of corresponding EAX is 1 or
not.
Leaf 7 follows the logic that EAX of subleaf 0 enumerates the maximum
valid subleaf.
Fixes: b9edbadefb ("i386: Propagate SGX CPUID sub-leafs to KVM")
Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Message-ID: <20240125024016.2521244-4-xiaoyao.li@intel.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
This commit extends the APIC ID to 32-bit long and remove the 255 max APIC
ID limit in userspace APIC. The array that manages local APICs is now
dynamically allocated based on the max APIC ID of created x86 machine.
Also, new x2APIC IPI destination determination scheme, self IPI and x2APIC
mode register access are supported.
Signed-off-by: Bui Quang Minh <minhquangbui99@gmail.com>
Message-Id: <20240111154404.5333-3-minhquangbui99@gmail.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
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>
For user-only mode, use MMU_USER_IDX.
For system mode, use CPUClass.mmu_index.
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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>
uintptr_t, or unsigned long which is equivalent on Linux I32LP64 systems,
is an unsigned type and there is no need to further cast to __u64 which is
another unsigned integer type; widening casts from unsigned integers
zero-extend the value.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
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>
