While most features are now detected by probing the ID_* registers
kernels can (and do) use MIDR_EL1 for working out of they have to
apply errata. This can trip up warnings in the kernel as it tries to
work out if it should apply workarounds to features that don't
actually exist in the reported CPU type.
Avoid this problem by synthesising our own MIDR value.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
---
v2
- don't leak QEMU version into ID reg
v3
- move comment into one block
- explicit setting of more fields
v4
- minor reword of comment
v5
- VARIANT->PARTNUM and extra words
---
target/arm/cpu.h | 6 ++++++
target/arm/cpu64.c | 19 +++++++++++++++++++
2 files changed, 25 insertions(+)
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 94c990cddbd..67f2af0e169 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -1611,6 +1611,12 @@ FIELD(V7M_FPCCR, ASPEN, 31, 1)
/*
* System register ID fields.
*/
+FIELD(MIDR_EL1, REVISION, 0, 4)
+FIELD(MIDR_EL1, PARTNUM, 4, 12)
+FIELD(MIDR_EL1, ARCHITECTURE, 16, 4)
+FIELD(MIDR_EL1, VARIANT, 20, 4)
+FIELD(MIDR_EL1, IMPLEMENTER, 24, 8)
+
FIELD(ID_ISAR0, SWAP, 0, 4)
FIELD(ID_ISAR0, BITCOUNT, 4, 4)
FIELD(ID_ISAR0, BITFIELD, 8, 4)
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 1901997a064..ee55237a9b2 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -296,6 +296,25 @@ static void aarch64_max_initfn(Object *obj)
uint32_t u;
aarch64_a57_initfn(obj);
+ /*
+ * Reset MIDR so the guest doesn't mistake our 'max' CPU type for a real
+ * one and try to apply errata workarounds or use impdef features we
+ * don't provide.
+ * An IMPLEMENTER field of 0 means "reserved for software use";
+ * ARCHITECTURE must be 0xf indicating "v7 or later, check ID registers
+ * to see which features are present";
+ * the VARIANT, PARTNUM and REVISION fields are all implementation
+ * defined and we choose to define PARTNUM just in case guest
+ * code needs to distinguish this QEMU CPU from other software
+ * implementations, though this shouldn't be needed.
+ */
+ t = FIELD_DP64(0, MIDR_EL1, IMPLEMENTER, 0);
+ t = FIELD_DP64(t, MIDR_EL1, ARCHITECTURE, 0xf);
+ t = FIELD_DP64(t, MIDR_EL1, PARTNUM, 'Q');
+ t = FIELD_DP64(t, MIDR_EL1, VARIANT, 0);
+ t = FIELD_DP64(t, MIDR_EL1, REVISION, 0);
+ cpu->midr = t;
+
t = cpu->isar.id_aa64isar0;
t = FIELD_DP64(t, ID_AA64ISAR0, AES, 2); /* AES + PMULL */
t = FIELD_DP64(t, ID_AA64ISAR0, SHA1, 1);
--
2.20.1
Patchew URL: https://patchew.org/QEMU/20190726113950.7499-1-alex.bennee@linaro.org/ Hi, This series seems to have some coding style problems. See output below for more information: Type: series Subject: [Qemu-devel] [PATCH v5] target/arm: generate a custom MIDR for -cpu max Message-id: 20190726113950.7499-1-alex.bennee@linaro.org === TEST SCRIPT BEGIN === #!/bin/bash git rev-parse base > /dev/null || exit 0 git config --local diff.renamelimit 0 git config --local diff.renames True git config --local diff.algorithm histogram ./scripts/checkpatch.pl --mailback base.. === TEST SCRIPT END === Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384 From https://github.com/patchew-project/qemu * [new tag] patchew/20190726113950.7499-1-alex.bennee@linaro.org -> patchew/20190726113950.7499-1-alex.bennee@linaro.org Submodule 'capstone' (https://git.qemu.org/git/capstone.git) registered for path 'capstone' Submodule 'dtc' (https://git.qemu.org/git/dtc.git) registered for path 'dtc' Submodule 'roms/QemuMacDrivers' (https://git.qemu.org/git/QemuMacDrivers.git) registered for path 'roms/QemuMacDrivers' Submodule 'roms/SLOF' (https://git.qemu.org/git/SLOF.git) registered for path 'roms/SLOF' Submodule 'roms/edk2' (https://git.qemu.org/git/edk2.git) registered for path 'roms/edk2' Submodule 'roms/ipxe' (https://git.qemu.org/git/ipxe.git) registered for path 'roms/ipxe' Submodule 'roms/openbios' (https://git.qemu.org/git/openbios.git) registered for path 'roms/openbios' Submodule 'roms/openhackware' (https://git.qemu.org/git/openhackware.git) registered for path 'roms/openhackware' Submodule 'roms/opensbi' (https://git.qemu.org/git/opensbi.git) registered for path 'roms/opensbi' Submodule 'roms/qemu-palcode' (https://git.qemu.org/git/qemu-palcode.git) registered for path 'roms/qemu-palcode' Submodule 'roms/seabios' (https://git.qemu.org/git/seabios.git/) registered for path 'roms/seabios' Submodule 'roms/seabios-hppa' (https://git.qemu.org/git/seabios-hppa.git) registered for path 'roms/seabios-hppa' Submodule 'roms/sgabios' (https://git.qemu.org/git/sgabios.git) registered for path 'roms/sgabios' Submodule 'roms/skiboot' (https://git.qemu.org/git/skiboot.git) registered for path 'roms/skiboot' Submodule 'roms/u-boot' (https://git.qemu.org/git/u-boot.git) registered for path 'roms/u-boot' Submodule 'roms/u-boot-sam460ex' (https://git.qemu.org/git/u-boot-sam460ex.git) registered for path 'roms/u-boot-sam460ex' Submodule 'slirp' (https://git.qemu.org/git/libslirp.git) registered for path 'slirp' Submodule 'tests/fp/berkeley-softfloat-3' (https://git.qemu.org/git/berkeley-softfloat-3.git) registered for path 'tests/fp/berkeley-softfloat-3' Submodule 'tests/fp/berkeley-testfloat-3' (https://git.qemu.org/git/berkeley-testfloat-3.git) registered for path 'tests/fp/berkeley-testfloat-3' Submodule 'ui/keycodemapdb' (https://git.qemu.org/git/keycodemapdb.git) registered for path 'ui/keycodemapdb' Cloning into 'capstone'... Submodule path 'capstone': checked out '22ead3e0bfdb87516656453336160e0a37b066bf' Cloning into 'dtc'... Submodule path 'dtc': checked out '88f18909db731a627456f26d779445f84e449536' Cloning into 'roms/QemuMacDrivers'... Submodule path 'roms/QemuMacDrivers': checked out '90c488d5f4a407342247b9ea869df1c2d9c8e266' Cloning into 'roms/SLOF'... Submodule path 'roms/SLOF': checked out 'ba1ab360eebe6338bb8d7d83a9220ccf7e213af3' Cloning into 'roms/edk2'... Submodule path 'roms/edk2': checked out '20d2e5a125e34fc8501026613a71549b2a1a3e54' Submodule 'SoftFloat' (https://github.com/ucb-bar/berkeley-softfloat-3.git) registered for path 'ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3' Submodule 'CryptoPkg/Library/OpensslLib/openssl' (https://github.com/openssl/openssl) registered for path 'CryptoPkg/Library/OpensslLib/openssl' Cloning into 'ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3'... Submodule path 'roms/edk2/ArmPkg/Library/ArmSoftFloatLib/berkeley-softfloat-3': checked out 'b64af41c3276f97f0e181920400ee056b9c88037' Cloning into 'CryptoPkg/Library/OpensslLib/openssl'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl': checked out '50eaac9f3337667259de725451f201e784599687' Submodule 'boringssl' (https://boringssl.googlesource.com/boringssl) registered for path 'boringssl' Submodule 'krb5' (https://github.com/krb5/krb5) registered for path 'krb5' Submodule 'pyca.cryptography' (https://github.com/pyca/cryptography.git) registered for path 'pyca-cryptography' Cloning into 'boringssl'... Submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl/boringssl': checked out '2070f8ad9151dc8f3a73bffaa146b5e6937a583f' Cloning into 'krb5'... fatal: unable to access 'https://github.com/krb5/krb5/': Could not resolve host: github.com; Name or service not known Clone of 'https://github.com/krb5/krb5' into submodule path 'krb5' failed Failed to recurse into submodule path 'roms/edk2/CryptoPkg/Library/OpensslLib/openssl' Cloning into 'roms/ipxe'... Submodule path 'roms/ipxe': checked out 'de4565cbe76ea9f7913a01f331be3ee901bb6e17' Cloning into 'roms/openbios'... Submodule path 'roms/openbios': checked out 'c79e0ecb84f4f1ee3f73f521622e264edd1bf174' Cloning into 'roms/openhackware'... Submodule path 'roms/openhackware': checked out 'c559da7c8eec5e45ef1f67978827af6f0b9546f5' Cloning into 'roms/opensbi'... Submodule path 'roms/opensbi': checked out 'ce228ee0919deb9957192d723eecc8aaae2697c6' Cloning into 'roms/qemu-palcode'... Submodule path 'roms/qemu-palcode': checked out 'bf0e13698872450164fa7040da36a95d2d4b326f' Cloning into 'roms/seabios'... Submodule path 'roms/seabios': checked out 'a5cab58e9a3fb6e168aba919c5669bea406573b4' Cloning into 'roms/seabios-hppa'... Submodule path 'roms/seabios-hppa': checked out '0f4fe84658165e96ce35870fd19fc634e182e77b' Cloning into 'roms/sgabios'... Submodule path 'roms/sgabios': checked out 'cbaee52287e5f32373181cff50a00b6c4ac9015a' Cloning into 'roms/skiboot'... Submodule path 'roms/skiboot': checked out '261ca8e779e5138869a45f174caa49be6a274501' Cloning into 'roms/u-boot'... Submodule path 'roms/u-boot': checked out 'd3689267f92c5956e09cc7d1baa4700141662bff' Cloning into 'roms/u-boot-sam460ex'... Submodule path 'roms/u-boot-sam460ex': checked out '60b3916f33e617a815973c5a6df77055b2e3a588' Cloning into 'slirp'... Submodule path 'slirp': checked out 'f0da6726207b740f6101028b2992f918477a4b08' Cloning into 'tests/fp/berkeley-softfloat-3'... Submodule path 'tests/fp/berkeley-softfloat-3': checked out 'b64af41c3276f97f0e181920400ee056b9c88037' Cloning into 'tests/fp/berkeley-testfloat-3'... Submodule path 'tests/fp/berkeley-testfloat-3': checked out '5a59dcec19327396a011a17fd924aed4fec416b3' Cloning into 'ui/keycodemapdb'... Submodule path 'ui/keycodemapdb': checked out '6b3d716e2b6472eb7189d3220552280ef3d832ce' Failed to recurse into submodule path 'roms/edk2' Traceback (most recent call last): File "./patchew-cli", line 504, in test_one git_clone_repo(clone, r["repo"], r["head"], logf) File "./patchew-cli", line 50, in git_clone_repo stderr=logf, stdout=logf) File "/usr/lib64/python3.4/subprocess.py", line 558, in check_call raise CalledProcessError(retcode, cmd) subprocess.CalledProcessError: Command '['git', 'clone', '-q', '--recursive', '/home/patchew/.cache/patchew-git-cache/httpsgithubcompatchewprojectqemu-3c8cf5a9c21ff8782164d1def7f44bd888713384', '/var/tmp/patchew-tester-tmp-13u3_z0m/src']' returned non-zero exit status 1 The full log is available at http://patchew.org/logs/20190726113950.7499-1-alex.bennee@linaro.org/testing.checkpatch/?type=message. --- Email generated automatically by Patchew [https://patchew.org/]. Please send your feedback to patchew-devel@redhat.com
On 7/26/19 4:39 AM, Alex Bennée wrote: > While most features are now detected by probing the ID_* registers > kernels can (and do) use MIDR_EL1 for working out of they have to > apply errata. This can trip up warnings in the kernel as it tries to > work out if it should apply workarounds to features that don't > actually exist in the reported CPU type. > > Avoid this problem by synthesising our own MIDR value. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > Reviewed-by: Peter Maydell <peter.maydell@linaro.org> > > --- > v2 > - don't leak QEMU version into ID reg > v3 > - move comment into one block > - explicit setting of more fields > v4 > - minor reword of comment > v5 > - VARIANT->PARTNUM and extra words > --- > target/arm/cpu.h | 6 ++++++ > target/arm/cpu64.c | 19 +++++++++++++++++++ > 2 files changed, 25 insertions(+) Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~
On Fri, 26 Jul 2019 at 12:39, Alex Bennée <alex.bennee@linaro.org> wrote: > > While most features are now detected by probing the ID_* registers > kernels can (and do) use MIDR_EL1 for working out of they have to > apply errata. This can trip up warnings in the kernel as it tries to > work out if it should apply workarounds to features that don't > actually exist in the reported CPU type. > > Avoid this problem by synthesising our own MIDR value. > > Signed-off-by: Alex Bennée <alex.bennee@linaro.org> > Reviewed-by: Peter Maydell <peter.maydell@linaro.org> > > --- > v2 > - don't leak QEMU version into ID reg > v3 > - move comment into one block > - explicit setting of more fields > v4 > - minor reword of comment > v5 > - VARIANT->PARTNUM and extra words Applied to target-arm.next for 4.2, thanks. -- PMM
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