Bus lock debug exception is a feature that can notify the kernel by
generate an #DB trap after the instruction acquires a bus lock when
CPL>0. This allows the kernel to enforce user application throttling or
mitigations.
This feature is enumerated via CPUID.(EAX=7,ECX=0).ECX[bit 24].
Backports 06e878b413766778a53be3d25c0373a23679d039
We were fudging TBI1 enabled to speed up the generated code.
Now that we've improved the code generation, remove this.
Also, tidy the comment to reflect the current code.
The pauth test was testing a kernel address (-1) and making
incorrect assumptions about TBI1; stick to userland addresses.
Backports 16c849784873d10d0da257d698e391fddea1f0e4
When working with performance monitoring counters, we look at
MDCR_EL2.HPMN as part of the check whether a counter is enabled. This
check fails, because MDCR_EL2.HPMN is reset to 0, meaning that no
counters are "enabled" for < EL2.
That's in violation of the Arm specification, which states that
> On a Warm reset, this field [MDCR_EL2.HPMN] resets to the value in
> PMCR_EL0.N
That's also what a comment in the code acknowledges, but the necessary
adjustment seems to have been forgotten when support for more counters
was added.
This change fixes the issue by setting the reset value to PMCR.N, which
is four.
Backports d3c1183ffeb71ca3a783eae3d7e1c51e71e8a621
cpsr has been treated as being the same as spsr, but it isn't.
Since PSTATE_SS isn't in cpsr, remove it and move it into env->pstate.
This allows us to add support for CPSR_DIT, adding helper functions
to merge SPSR_ELx to and from CPSR.
Backports f944a854ce4007000accf7c191b5b52916947198
Add support for FEAT_DIT. DIT (Data Independent Timing) is a required
feature for ARMv8.4. Since virtual machine execution is largely
nondeterministic and TCG is outside of the security domain, it's
implemented as a NOP.
Backports dc8b18534ea1dcc90d80ad9a61a3b0aa7eb312fb
The FW and AW bits of SCR_EL3 are RES1 only in some contexts. Force them
to 1 only when there is no support for AArch32 at EL1 or above.
The reset value will be 0x30 only if the CPU is AArch64-only; if there
is support for AArch32 at EL1 or above, it will be reset to 0.
Also adds helper function isar_feature_aa64_aa32_el1 to check if AArch32
is supported at EL1 or above.
Backports 10d0ef3e6cfe228df4b2d3e27325f1b0e2b71fd5
Expose the VMX exit/entry load pkrs control bits in
VMX_TRUE_EXIT_CTLS/VMX_TRUE_ENTRY_CTLS MSRs to guest, which supports the
PKS in nested VM.
Backports 52a44ad2b92ba4cd81c2b271cd5e4a2d820e91fc
Protection Keys for Supervisor-mode pages is a simple extension of
the PKU feature that QEMU already implements. For supervisor-mode
pages, protection key restrictions come from a new MSR. The MSR
has no XSAVE state associated to it.
PKS is only respected in long mode. However, in principle it is
possible to set the MSR even outside long mode, and in fact
even the XSAVE state for PKRU could be set outside long mode
using XRSTOR. So do not limit the migration subsections for
PKRU and PKRS to long mode.
Backports e7e7bdababeefff10736c6adf410c66d2f0d46fe
This patch fixes a translation bug for a subset of x86 BMI instructions
such as the following:
c4 e2 f9 f7 c0 shlxq %rax, %rax, %rax
Currently, these incorrectly generate an undefined instruction exception
when SSE is disabled via CR4, while instructions like "shrxq" work fine.
The problem appears to be related to BMI instructions encoded using VEX
and with a mandatory prefix of "0x66" (data). Instructions with this
data prefix (such as shlxq) are currently rejected. Instructions with
other mandatory prefixes (such as shrxq) translate as expected.
This patch removes the incorrect check in "gen_sse" that causes the
exception to be generated. For the non-BMI cases, the check is
redundant: prefixes are already checked at line 3696.
Buglink: https://bugs.launchpad.net/qemu/+bug/1748296
Backports 51909241d26fe6fe18a08def93ccc8273f61a8b3
32-bit targets by definition do not support long mode; therefore, the
bit must be masked in the features supported by the accelerator.
As a side effect, this avoids setting up the 0x80000008 CPUID leaf
for
qemu-system-i386 -cpu host
which since commit 5a140b255d ("x86/cpu: Use max host physical address
if -cpu max option is applied") would have printed this error:
qemu-system-i386: phys-bits should be between 32 and 36 (but is 48)
Backports 5ea9e9e239db83391a39c09f1de63c4099c20df5
commit 568496c0c0f1 ("cpu: Add callback to check architectural") and
commit 3826121d9298 ("target-arm: Implement checking of fired")
introduced an ARM-specific hack for cpu_check_watchpoint.
Make debug_check_watchpoint optional, and move it to tcg_ops.
Backports c73bdb35a91fb6b17c2c93b1ba381fc88a406f8d
commit 40612000599e ("arm: Correctly handle watchpoints for BE32 CPUs")
introduced this ARM-specific, TCG-specific hack to adjust the address,
before checking it with cpu_check_watchpoint.
Make adjust_watchpoint_address optional and move it to tcg_ops.
Backports 9ea9087bb4a86893e4ac6ff643837937dc9e5849
The TCG-specific CPU methods will be moved to a separate struct,
to make it easier to move accel-specific code outside generic CPU
code in the future. Start by moving tcg_initialize().
The new CPUClass.tcg_opts field may eventually become a pointer,
but keep it an embedded struct for now, to make code conversion
easier.
Backports e9e51b7154404efc9af8735ab87c658a9c434cfd
cc->do_interrupt is in theory a TCG callback used in accel/tcg only,
to prepare the emulated architecture to take an interrupt as defined
in the hardware specifications,
but in reality the _do_interrupt style of functions in targets are
also occasionally reused by KVM to prepare the architecture state in a
similar way where userspace code has identified that it needs to
deliver an exception to the guest.
In the case of ARM, that includes:
1) the vcpu thread got a SIGBUS indicating a memory error,
and we need to deliver a Synchronous External Abort to the guest to
let it know about the error.
2) the kernel told us about a debug exception (breakpoint, watchpoint)
but it is not for one of QEMU's own gdbstub breakpoints/watchpoints
so it must be a breakpoint the guest itself has set up, therefore
we need to deliver it to the guest.
So in order to reuse code, the same arm_do_interrupt function is used.
This is all fine, but we need to avoid calling it using the callback
registered in CPUClass, since that one is now TCG-only.
Fortunately this is easily solved by replacing calls to
CPUClass::do_interrupt() with explicit calls to arm_do_interrupt().
Backports 853bfef4e6d60244fd131ec55bbf1e7caa52599b. We don't support
KVM, so we just bring the comment addition over.
This was defined at some point before ARMv8.4, and will
shortly be used by new processor descriptions.
Backports 1d51bc96cc4a9b2d31a3f4cb8442ce47753088e2
When building with GCC 10.2 configured with --extra-cflags=-Os, we get:
target/arm/m_helper.c: In function ‘arm_v7m_cpu_do_interrupt’:
target/arm/m_helper.c:1811:16: error: ‘restore_s16_s31’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
1811 | if (restore_s16_s31) {
| ^
target/arm/m_helper.c:1350:10: note: ‘restore_s16_s31’ was declared here
1350 | bool restore_s16_s31;
| ^~~~~~~~~~~~~~~
cc1: all warnings being treated as errors
Initialize the 'restore_s16_s31' variable to silence the warning.
Backports 0ae4f11ee57350dac0e705ba79516310400ff43c
These two were odd, in that do_pfirst_pnext passed the
count of 64-bit words rather than bytes. Change to pass
the standard pred_full_reg_size to avoid confusion.
Backports 86300b5d044064046395ae8ed605cc19e63f2a7c
SVE predicate operations cannot use the "usual" simd_desc
encoding, because the lengths are not a multiple of 8.
But we were abusing the SIMD_* fields to store values anyway.
This abuse broke when SIMD_OPRSZ_BITS was modified in e2e7168a214.
Introduce a new set of field definitions for exclusive use
of predicates, so that it is obvious what kind of predicate
we are manipulating. To be used in future patches
Backports b64ee454a4a086ed459bcda4c0bbb54e197841e4
On ARMv8-A, accesses by 32-bit secure EL1 to monitor registers trap to
the upper (64-bit) EL. With Secure EL2 support, we can no longer assume
that that is always EL3, so make room for the value to be computed at
run-time.
Backports 6b340aeb48e4f7f983e1c38790de65ae93079840
The stage_1_mmu_idx() already effectively keeps track of which
translation regimes have two stages. Don't hard-code another test.
Backports 7879460a6149ed5e80c29cac85449191d9c5754a
In the secure stage 2 translation regime, the VSTCR.SW and VTCR.NSW
bits can invert the secure flag for pagetable walks. This patchset
allows S1_ptw_translate() to change the non-secure bit.
Backports 3d4bd397433b12b148d150c8bc5655a696389bd1
The VTTBR write callback so far assumes that the underlying VM lies in
non-secure state. This handles the secure state scenario.
backports c4f060e89effd70ebdb23d3315495d33af377a09
This adds the MMU indices for EL2 stage 1 in secure state.
To keep code contained, which is largelly identical between secure and
non-secure modes, the MMU indices are reassigned. The new assignments
provide a systematic pattern with a non-secure bit.
Backports b6ad6062f1e55bd5b9407ce89e55e3a08b83827c
With the ARMv8.4-SEL2 extension, EL2 is a legal exception level in
secure mode, though it can only be AArch64.
This patch adds the target EL for exceptions from 64-bit S-EL2.
It also fixes the target EL to EL2 when HCR.{A,F,I}MO are set in secure
mode. Those values were never used in practice as the effective value of
HCR was always 0 in secure mode.
Backports 6c85f906261226e87211506bd9f787fd48a09f17
This adds a common helper to compute the effective value of MDCR_EL2.
That is the actual value if EL2 is enabled in the current security
context, or 0 elsewise.
Backports 59dd089cf9e4a9cddee596c8a1378620df51b9bb
Do not assume that EL2 is available in and only in non-secure context.
That equivalence is broken by ARMv8.4-SEL2.
Backports e6ef0169264b00cce552404f689ce137018ff290
In this context, the HCR value is the effective value, and thus is
zero in secure mode. The tests for HCR.{F,I}MO are sufficient.
Backports cc974d5cd84ea60a3dad59752aea712f3d47f8ce
The crypto overhead of emulating pauth can be significant for
some workloads. Add two boolean properties that allows the
feature to be turned off, on with the architected algorithm,
or on with an implementation defined algorithm.
We need two intermediate booleans to control the state while
parsing properties lest we clobber ID_AA64ISAR1 into an invalid
intermediate state.
Backports relevent members from eb94284d0812b4e7c11c5d075b584100ac1c1b9a
Without hardware acceleration, a cryptographically strong
algorithm is too expensive for pauth_computepac.
Even with hardware accel, we are not currently expecting
to link the linux-user binaries to any crypto libraries,
and doing so would generally make the --static build fail.
So choose XXH64 as a reasonably quick and decent hash.
Backports 283fc52ade85eb50141f3b8b85f82b07d016cb17
In commit cd8be50e58f63413c0 we converted the A32 coprocessor
insns to decodetree. This accidentally broke XScale/iWMMXt insns,
because it moved the handling of "cp insns which are handled
by looking up the cp register in the hashtable" from after the
call to the legacy disas_xscale_insn() decode to before it,
with the result that all XScale/iWMMXt insns now UNDEF.
Update valid_cp() so that it knows that on XScale cp 0 and 1
are not standard coprocessor instructions; this will cause
the decodetree trans_ functions to ignore them, so that
execution will correctly get through to the legacy decode again.
Backports e4d51ac6921dc861bfb3d20e4c7dcf345840a9da
When FEAT_MTE is implemented, the AArch64 view of CTR_EL0 adds the
TminLine field in bits [37:32].
Extend the ctr field to be able to hold this context.
Backports a5fd319ae7f6d496ff5448ec1dedcae8e2f59e9f
The AArch64 view of CLIDR_EL1 extends the ICB field to include also bit
32, as well as adding a Ttype<n> field when FEAT_MTE is implemented.
Extend the clidr field to be able to hold this context.
Backports f6450bcb6b2d3e4beae77141edce9e99cb8c277e
Now that we have implemented all the features needed by the v8.1M
architecture, we can add the model of the Cortex-M55. This is the
configuration without MVE support; we'll add MVE later
Backports 590e05d6b48937f6d3c631354fd706f8e005b8f6
Implement the v8.1M FPCXT_NS floating-point system register. This is
a little more complicated than FPCXT_S, because it has specific
handling for "current FP state is inactive", and it only wants to do
PreserveFPState(), not the full set of actions done by
ExecuteFPCheck() which vfp_access_check() implements.
Backports eb20dafdbff92063a88624176fdc396e01961bf3
In commit 64f863baeedc8659 we implemented the v8.1M FPCXT_S register,
but we got the write behaviour wrong. On read, this register reads
bits [27:0] of FPSCR plus the CONTROL.SFPA bit. On write, it doesn't
just write back those bits -- it writes a value to the whole FPSCR,
whose upper 4 bits are zeroes.
We also incorrectly implemented the write-to-FPSCR as a simple store
to vfp.xregs; this skips the "update the softfloat flags" part of
the vfp_set_fpscr helper so the value would read back correctly but
not actually take effect.
Fix both of these things by doing a complete write to the FPSCR
using the helper function.
Backports 7fbf95a037d79c5e923ffb51ac902dbe9599c87f
In 50244cc76abc we updated mte_check_fail to match the ARM
pseudocode, using the correct EL to select the TCF field.
But we failed to update MTE0_ACTIVE the same way, which led
to g_assert_not_reached().
Backports cc97b0019bb590b9b3c2a623e9ebee48831e0ce3
When the 'int N' instruction is executed in protected mode, the
pseudocode in the architecture manual specifies that we need to check:
* vector number within IDT limits
* selected IDT descriptor is a valid type (interrupt, trap or task gate)
* if this was a software interrupt then gate DPL < CPL
The way we had structured the code meant that the privilege check for
software interrupts ended up not in the code path taken for task gate
handling, because all of the task gate handling code was in the 'case 5'
of the switch which was checking "is this descriptor a valid type".
Move the task gate handling code out of that switch (so that it is now
purely doing the "valid type?" check) and below the software interrupt
privilege check.
The effect of this missing check was that in a guest userspace binary
executing 'int 8' would cause a guest kernel panic rather than the
userspace binary being handed a SEGV.
This is essentially the same bug fixed in VirtualBox in 2012:
https://www.halfdog.net/Security/2012/VirtualBoxSoftwareInterrupt0x8GuestCrash/
Note that for QEMU this is not a security issue because it is only
present when using TCG.
Backports 3df1a3d070575419859cbbab1083fafa7ec2669a
I found that there are many spelling errors in the comments of qemu/target/m68k.
I used spellcheck to check the spelling errors and found some errors in the folder.
Backports ce00ff729ee8461dc94a1593d25ceda65d973d3c
Per the SDM, when returning to outer privilege level, for segment
registers (ES, FS, GS, and DS) if the check fails, the segment
selector becomes null, but QEMU clears the base/limit/flags as well
as nullifying the segment selector, which should be a spec violation.
Real hardware seems to be compliant with the spec, at least on one
Coffee Lake board I tested.
Backports c2ba0515f2df58a661fcb5d6485139877d92ab1b
For PDEP and PEXT, the mask is provided in the memory (mod+r/m)
operand, and therefore is loaded in s->T0 by gen_ldst_modrm.
The source is provided in the second source operand (VEX.vvvv)
and therefore is loaded in s->T1. Fix the order in which
they are passed to the helpers.
Backports 75b208c28316095c4685e8596ceb9e3f656592e2
For v8.1M the architecture mandates that CPUs must provide at
least the "minimal RAS implementation" from the Reliability,
Availability and Serviceability extension. This consists of:
* an ESB instruction which is a NOP
-- since it is in the HINT space we need only add a comment
* an RFSR register which will RAZ/WI
* a RAZ/WI AIRCR.IESB bit
-- the code which handles writes to AIRCR does not allow setting
of RES0 bits, so we already treat this as RAZ/WI; add a comment
noting that this is deliberate
* minimal implementation of the RAS register block at 0xe0005000
-- this will be in a subsequent commit
* setting the ID_PFR0.RAS field to 0b0010
-- we will do this when we add the Cortex-M55 CPU model
Backports 46f4976f22a4549322307b34272e053d38653243
v8.1M introduces a new TRD flag in the CCR register, which enables
checking for stack frame integrity signatures on SG instructions.
Add the code in the SG insn implementation for the new behaviour.
Backports 7f484147369080d36c411c4ba969f90d025aed55
