| Message ID | 20241217090707.3511160-1-cleger@rivosinc.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | target/riscv: Add support for Smdbltrp and Ssdbltrp extensions | expand |
On Tue, Dec 17, 2024 at 7:10 PM Clément Léger <cleger@rivosinc.com> wrote: > > A double trap typically arises during a sensitive phase in trap handling > operations — when an exception or interrupt occurs while the trap > handler (the component responsible for managing these events) is in a > non-reentrant state. This non-reentrancy usually occurs in the early > phase of trap handling, wherein the trap handler has not yet preserved > the necessary state to handle and resume from the trap. The occurrence > of such event is unlikely but can happen when dealing with hardware > errors. > > This series adds support for Ssdbltrp and Smdbltrp ratified ISA > extensions [1]. It is based on the Smrnmi series [5]. > > Ssdbltrp can be tested using qemu[2], opensbi (master branch), linux[3] and > kvm-unit-tests[4]. Assuming you have a riscv environment available and > configured (CROSS_COMPILE), it can be built for riscv64 using the > following instructions: > > Qemu: > $ git clone https://github.com/rivosinc/qemu.git > $ cd qemu > $ git switch -C dbltrp_v6 dev/cleger/dbltrp_v6 > $ mkdir build && cd build > $ ../configure --target-list=riscv64-softmmu > $ make > > OpenSBI: > $ git clone https://github.com/rivosinc/opensbi.git > $ cd opensbi > $ make O=build PLATFORM_RISCV_XLEN=64 PLATFORM=generic > > Linux: > $ git clone https://github.com/rivosinc/linux.git > $ cd linux > $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 > $ export ARCH=riscv > $ make O=build defconfig > $ ./script/config --file build/.config --enable RISCV_DBLTRP > $ make O=build > > kvm-unit-tests: > $ git clone https://github.com/clementleger/kvm-unit-tests.git > $ cd kvm-unit-tests > $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 > $ ./configure --arch=riscv64 --cross-prefix=$CROSS_COMPILE > $ make > > You will also need kvmtool in your rootfs. > > Run with kvm-unit-test test as kernel: > $ qemu-system-riscv64 \ > -M virt \ > -cpu rv64,ssdbltrp=true,smdbltrp=true \ > -nographic \ > -serial mon:stdio \ > -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ > -kernel kvm-unit-tests-dbltrp/riscv/sbi_dbltrp.flat > ... > [OpenSBI boot partially elided] > Boot HART ISA Extensions : sscofpmf,sstc,zicntr,zihpm,zicboz,zicbom,sdtrig,svadu,ssdbltrp > ... > ########################################################################## > # kvm-unit-tests > ########################################################################## > > PASS: sbi: fwft: FWFT extension probing no error > PASS: sbi: fwft: FWFT extension is present > PASS: sbi: fwft: dbltrp: Get double trap enable feature value > PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 > PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 > PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok > PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 > PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 > PASS: sbi: fwft: dbltrp: Trapped twice allowed ok > INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! > > sbi_trap_error: hart0: trap0: double trap handler failed (error -10) > > sbi_trap_error: hart0: trap0: mcause=0x0000000000000010 mtval=0x0000000000000000 > sbi_trap_error: hart0: trap0: mtval2=0x0000000000000003 mtinst=0x0000000000000000 > sbi_trap_error: hart0: trap0: mepc=0x00000000802000d8 mstatus=0x8000000a01006900 > sbi_trap_error: hart0: trap0: ra=0x00000000802001fc sp=0x0000000080213e70 > sbi_trap_error: hart0: trap0: gp=0x0000000000000000 tp=0x0000000080088000 > sbi_trap_error: hart0: trap0: s0=0x0000000080213e80 s1=0x0000000000000001 > sbi_trap_error: hart0: trap0: a0=0x0000000080213e80 a1=0x0000000080208193 > sbi_trap_error: hart0: trap0: a2=0x000000008020dc20 a3=0x000000000000000f > sbi_trap_error: hart0: trap0: a4=0x0000000080210cd8 a5=0x00000000802110d0 > sbi_trap_error: hart0: trap0: a6=0x00000000802136e4 a7=0x0000000046574654 > sbi_trap_error: hart0: trap0: s2=0x0000000080210cd9 s3=0x0000000000000000 > sbi_trap_error: hart0: trap0: s4=0x0000000000000000 s5=0x0000000000000000 > sbi_trap_error: hart0: trap0: s6=0x0000000000000000 s7=0x0000000000000001 > sbi_trap_error: hart0: trap0: s8=0x0000000000002000 s9=0x0000000080083700 > sbi_trap_error: hart0: trap0: s10=0x0000000000000000 s11=0x0000000000000000 > sbi_trap_error: hart0: trap0: t0=0x0000000000000000 t1=0x0000000080213ed8 > sbi_trap_error: hart0: trap0: t2=0x0000000000001000 t3=0x0000000080213ee0 > sbi_trap_error: hart0: trap0: t4=0x0000000000000000 t5=0x000000008020f8d0 > sbi_trap_error: hart0: trap0: t6=0x0000000000000000 > > Run with linux and kvm-unit-test test in kvm (testing VS-mode): > $ qemu-system-riscv64 \ > -M virt \ > -cpu rv64,ssdbltrp=true,smdbltrp=true \ > -nographic \ > -serial mon:stdio \ > -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ > -kernel linux/build/arch/riscv/boot/Image > ... > [Linux boot partially elided] > [ 0.735079] riscv-dbltrp: Double trap handling registered > ... > > $ lkvm run -k sbi_dbltrp.flat -m 128 -c 2 > ########################################################################## > # kvm-unit-tests > ########################################################################## > > PASS: sbi: fwft: FWFT extension probing no error > PASS: sbi: fwft: FWFT extension is present > PASS: sbi: fwft: dbltrp: Get double trap enable feature value > PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 > PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 > PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok > PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 > PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 > PASS: sbi: fwft: dbltrp: Trapped twice allowed ok > INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! > [ 51.939077] Guest double trap > [ 51.939323] kvm [93]: VCPU exit error -95 > [ 51.939683] kvm [93]: SEPC=0x802000d8 SSTATUS=0x200004520 HSTATUS=0x200200180 > [ 51.939947] kvm [93]: SCAUSE=0x10 STVAL=0x0 HTVAL=0x3 HTINST=0x0 > KVM_RUN failed: Operation not supported > $ > > Testing Smbdbltrp can be done using gdb and trigger some trap. For > instance, interrupt M-mode firmware at some point, set mstatus.mdt = 1 > and corrupt some register to generate a NULL pointer exception. > > Link: https://github.com/riscv/riscv-isa-manual/commit/52a5742d5ab5a0792019033631b2035a493ad981 [1] > Link: https://github.com/rivosinc/qemu/tree/dev/cleger/dbltrp_v7 [2] > Link: https://github.com/rivosinc/linux/tree/dev/cleger/dbltrp_v1 [3] > Link: https://github.com/clementleger/kvm-unit-tests/tree/dev/cleger/dbltrp_v1 [4] > Link: https://lore.kernel.org/qemu-riscv/20241217062440.884261-1-frank.chang@sifive.com/ [5] > > --- > > V7: > - Rebased on riscv-to-apply.next, on top of snrmi v10 series Sorry for asking again, but can you do another rebase on https://github.com/alistair23/qemu/tree/riscv-to-apply.next ? All these new extensions are conflicting a lot unfortunately, but at least snrmi has been merged :) Alistair > > V6: > - Simplify and fix write_henvcfg() masking by assigning the written > value to henvcfg and mask the value to be written as well as clearing > the upper part of henvcfgh upon writing. > - Rebased on RNMI v9 series. > > V5: > - Use 0 instead of false to set MSTATUS_MDT in helper_mnret() > - Added explicit comments about henvcfg write mask being tricky. > - Fixed a invalid menvcfg_mask in write_henvcfgh > > V4: > - Remove DTE from sstatus_v1_10_mask variable and add specific if for > DTE masking where it's used. > - Use mstatus_hs.sdt field rather than setting DTE to 0 in > riscv_do_cpu_interrupt(). > - Add a fix for henvcfg value which was incorrectly set after changing > menvcfg > - Remove useless ext_ssdbltrp check in > riscv_env_smode_dbltrp_enabled(). > - Remove useless mstatus clear in write_mstatus(). > - Add proper handling of SDT writing to vsstatus. > - Add clearing of vsstatus//mstatus SDT field when DTE is disabled. > - Fix wrong value being written for MDT/MIE in write_mstatush(). > - Rebased on Frank Snrnmi v7 > > V3: > - Fix spec version from 1.12 to 1.13 for Smdbltrp and Ssdbltrp > - Add better comments for dte/sdt computation in > riscv_cpu_do_interrupt(). > - Move some CSR related changes to the CSRs related commits. > > V2: > - Squashed commits that added ext_s{s|m}dbltrp as suggested by Daniel > > Clément Léger (9): > target/riscv: Fix henvcfg potentially containing stale bits > target/riscv: Add Ssdbltrp CSRs handling > target/riscv: Implement Ssdbltrp sret, mret and mnret behavior > target/riscv: Implement Ssdbltrp exception handling > target/riscv: Add Ssdbltrp ISA extension enable switch > target/riscv: Add Smdbltrp CSRs handling > target/riscv: Implement Smdbltrp sret, mret and mnret behavior > target/riscv: Implement Smdbltrp behavior > target/riscv: Add Smdbltrp ISA extension enable switch > > target/riscv/cpu.c | 9 ++- > target/riscv/cpu.h | 1 + > target/riscv/cpu_bits.h | 8 +++ > target/riscv/cpu_cfg.h | 2 + > target/riscv/cpu_helper.c | 115 +++++++++++++++++++++++++++++++------- > target/riscv/csr.c | 95 ++++++++++++++++++++++++++----- > target/riscv/op_helper.c | 47 +++++++++++++++- > 7 files changed, 239 insertions(+), 38 deletions(-) > > -- > 2.45.2 > >
On 10/01/2025 03:12, Alistair Francis wrote: > On Tue, Dec 17, 2024 at 7:10 PM Clément Léger <cleger@rivosinc.com> wrote: >> >> A double trap typically arises during a sensitive phase in trap handling >> operations — when an exception or interrupt occurs while the trap >> handler (the component responsible for managing these events) is in a >> non-reentrant state. This non-reentrancy usually occurs in the early >> phase of trap handling, wherein the trap handler has not yet preserved >> the necessary state to handle and resume from the trap. The occurrence >> of such event is unlikely but can happen when dealing with hardware >> errors. >> >> This series adds support for Ssdbltrp and Smdbltrp ratified ISA >> extensions [1]. It is based on the Smrnmi series [5]. >> >> Ssdbltrp can be tested using qemu[2], opensbi (master branch), linux[3] and >> kvm-unit-tests[4]. Assuming you have a riscv environment available and >> configured (CROSS_COMPILE), it can be built for riscv64 using the >> following instructions: >> >> Qemu: >> $ git clone https://github.com/rivosinc/qemu.git >> $ cd qemu >> $ git switch -C dbltrp_v6 dev/cleger/dbltrp_v6 >> $ mkdir build && cd build >> $ ../configure --target-list=riscv64-softmmu >> $ make >> >> OpenSBI: >> $ git clone https://github.com/rivosinc/opensbi.git >> $ cd opensbi >> $ make O=build PLATFORM_RISCV_XLEN=64 PLATFORM=generic >> >> Linux: >> $ git clone https://github.com/rivosinc/linux.git >> $ cd linux >> $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 >> $ export ARCH=riscv >> $ make O=build defconfig >> $ ./script/config --file build/.config --enable RISCV_DBLTRP >> $ make O=build >> >> kvm-unit-tests: >> $ git clone https://github.com/clementleger/kvm-unit-tests.git >> $ cd kvm-unit-tests >> $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 >> $ ./configure --arch=riscv64 --cross-prefix=$CROSS_COMPILE >> $ make >> >> You will also need kvmtool in your rootfs. >> >> Run with kvm-unit-test test as kernel: >> $ qemu-system-riscv64 \ >> -M virt \ >> -cpu rv64,ssdbltrp=true,smdbltrp=true \ >> -nographic \ >> -serial mon:stdio \ >> -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ >> -kernel kvm-unit-tests-dbltrp/riscv/sbi_dbltrp.flat >> ... >> [OpenSBI boot partially elided] >> Boot HART ISA Extensions : sscofpmf,sstc,zicntr,zihpm,zicboz,zicbom,sdtrig,svadu,ssdbltrp >> ... >> ########################################################################## >> # kvm-unit-tests >> ########################################################################## >> >> PASS: sbi: fwft: FWFT extension probing no error >> PASS: sbi: fwft: FWFT extension is present >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value >> PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 >> PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok >> PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 >> PASS: sbi: fwft: dbltrp: Trapped twice allowed ok >> INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! >> >> sbi_trap_error: hart0: trap0: double trap handler failed (error -10) >> >> sbi_trap_error: hart0: trap0: mcause=0x0000000000000010 mtval=0x0000000000000000 >> sbi_trap_error: hart0: trap0: mtval2=0x0000000000000003 mtinst=0x0000000000000000 >> sbi_trap_error: hart0: trap0: mepc=0x00000000802000d8 mstatus=0x8000000a01006900 >> sbi_trap_error: hart0: trap0: ra=0x00000000802001fc sp=0x0000000080213e70 >> sbi_trap_error: hart0: trap0: gp=0x0000000000000000 tp=0x0000000080088000 >> sbi_trap_error: hart0: trap0: s0=0x0000000080213e80 s1=0x0000000000000001 >> sbi_trap_error: hart0: trap0: a0=0x0000000080213e80 a1=0x0000000080208193 >> sbi_trap_error: hart0: trap0: a2=0x000000008020dc20 a3=0x000000000000000f >> sbi_trap_error: hart0: trap0: a4=0x0000000080210cd8 a5=0x00000000802110d0 >> sbi_trap_error: hart0: trap0: a6=0x00000000802136e4 a7=0x0000000046574654 >> sbi_trap_error: hart0: trap0: s2=0x0000000080210cd9 s3=0x0000000000000000 >> sbi_trap_error: hart0: trap0: s4=0x0000000000000000 s5=0x0000000000000000 >> sbi_trap_error: hart0: trap0: s6=0x0000000000000000 s7=0x0000000000000001 >> sbi_trap_error: hart0: trap0: s8=0x0000000000002000 s9=0x0000000080083700 >> sbi_trap_error: hart0: trap0: s10=0x0000000000000000 s11=0x0000000000000000 >> sbi_trap_error: hart0: trap0: t0=0x0000000000000000 t1=0x0000000080213ed8 >> sbi_trap_error: hart0: trap0: t2=0x0000000000001000 t3=0x0000000080213ee0 >> sbi_trap_error: hart0: trap0: t4=0x0000000000000000 t5=0x000000008020f8d0 >> sbi_trap_error: hart0: trap0: t6=0x0000000000000000 >> >> Run with linux and kvm-unit-test test in kvm (testing VS-mode): >> $ qemu-system-riscv64 \ >> -M virt \ >> -cpu rv64,ssdbltrp=true,smdbltrp=true \ >> -nographic \ >> -serial mon:stdio \ >> -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ >> -kernel linux/build/arch/riscv/boot/Image >> ... >> [Linux boot partially elided] >> [ 0.735079] riscv-dbltrp: Double trap handling registered >> ... >> >> $ lkvm run -k sbi_dbltrp.flat -m 128 -c 2 >> ########################################################################## >> # kvm-unit-tests >> ########################################################################## >> >> PASS: sbi: fwft: FWFT extension probing no error >> PASS: sbi: fwft: FWFT extension is present >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value >> PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 >> PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok >> PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 >> PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 >> PASS: sbi: fwft: dbltrp: Trapped twice allowed ok >> INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! >> [ 51.939077] Guest double trap >> [ 51.939323] kvm [93]: VCPU exit error -95 >> [ 51.939683] kvm [93]: SEPC=0x802000d8 SSTATUS=0x200004520 HSTATUS=0x200200180 >> [ 51.939947] kvm [93]: SCAUSE=0x10 STVAL=0x0 HTVAL=0x3 HTINST=0x0 >> KVM_RUN failed: Operation not supported >> $ >> >> Testing Smbdbltrp can be done using gdb and trigger some trap. For >> instance, interrupt M-mode firmware at some point, set mstatus.mdt = 1 >> and corrupt some register to generate a NULL pointer exception. >> >> Link: https://github.com/riscv/riscv-isa-manual/commit/52a5742d5ab5a0792019033631b2035a493ad981 [1] >> Link: https://github.com/rivosinc/qemu/tree/dev/cleger/dbltrp_v7 [2] >> Link: https://github.com/rivosinc/linux/tree/dev/cleger/dbltrp_v1 [3] >> Link: https://github.com/clementleger/kvm-unit-tests/tree/dev/cleger/dbltrp_v1 [4] >> Link: https://lore.kernel.org/qemu-riscv/20241217062440.884261-1-frank.chang@sifive.com/ [5] >> >> --- >> >> V7: >> - Rebased on riscv-to-apply.next, on top of snrmi v10 series > > Sorry for asking again, but can you do another rebase on > https://github.com/alistair23/qemu/tree/riscv-to-apply.next ? > > All these new extensions are conflicting a lot unfortunately, but at > least snrmi has been merged :) Ahah no worries, I'll do that ! Thanks, Clément > > Alistair > >> >> V6: >> - Simplify and fix write_henvcfg() masking by assigning the written >> value to henvcfg and mask the value to be written as well as clearing >> the upper part of henvcfgh upon writing. >> - Rebased on RNMI v9 series. >> >> V5: >> - Use 0 instead of false to set MSTATUS_MDT in helper_mnret() >> - Added explicit comments about henvcfg write mask being tricky. >> - Fixed a invalid menvcfg_mask in write_henvcfgh >> >> V4: >> - Remove DTE from sstatus_v1_10_mask variable and add specific if for >> DTE masking where it's used. >> - Use mstatus_hs.sdt field rather than setting DTE to 0 in >> riscv_do_cpu_interrupt(). >> - Add a fix for henvcfg value which was incorrectly set after changing >> menvcfg >> - Remove useless ext_ssdbltrp check in >> riscv_env_smode_dbltrp_enabled(). >> - Remove useless mstatus clear in write_mstatus(). >> - Add proper handling of SDT writing to vsstatus. >> - Add clearing of vsstatus//mstatus SDT field when DTE is disabled. >> - Fix wrong value being written for MDT/MIE in write_mstatush(). >> - Rebased on Frank Snrnmi v7 >> >> V3: >> - Fix spec version from 1.12 to 1.13 for Smdbltrp and Ssdbltrp >> - Add better comments for dte/sdt computation in >> riscv_cpu_do_interrupt(). >> - Move some CSR related changes to the CSRs related commits. >> >> V2: >> - Squashed commits that added ext_s{s|m}dbltrp as suggested by Daniel >> >> Clément Léger (9): >> target/riscv: Fix henvcfg potentially containing stale bits >> target/riscv: Add Ssdbltrp CSRs handling >> target/riscv: Implement Ssdbltrp sret, mret and mnret behavior >> target/riscv: Implement Ssdbltrp exception handling >> target/riscv: Add Ssdbltrp ISA extension enable switch >> target/riscv: Add Smdbltrp CSRs handling >> target/riscv: Implement Smdbltrp sret, mret and mnret behavior >> target/riscv: Implement Smdbltrp behavior >> target/riscv: Add Smdbltrp ISA extension enable switch >> >> target/riscv/cpu.c | 9 ++- >> target/riscv/cpu.h | 1 + >> target/riscv/cpu_bits.h | 8 +++ >> target/riscv/cpu_cfg.h | 2 + >> target/riscv/cpu_helper.c | 115 +++++++++++++++++++++++++++++++------- >> target/riscv/csr.c | 95 ++++++++++++++++++++++++++----- >> target/riscv/op_helper.c | 47 +++++++++++++++- >> 7 files changed, 239 insertions(+), 38 deletions(-) >> >> -- >> 2.45.2 >> >>
A double trap typically arises during a sensitive phase in trap handling operations — when an exception or interrupt occurs while the trap handler (the component responsible for managing these events) is in a non-reentrant state. This non-reentrancy usually occurs in the early phase of trap handling, wherein the trap handler has not yet preserved the necessary state to handle and resume from the trap. The occurrence of such event is unlikely but can happen when dealing with hardware errors. This series adds support for Ssdbltrp and Smdbltrp ratified ISA extensions [1]. It is based on the Smrnmi series [5]. Ssdbltrp can be tested using qemu[2], opensbi (master branch), linux[3] and kvm-unit-tests[4]. Assuming you have a riscv environment available and configured (CROSS_COMPILE), it can be built for riscv64 using the following instructions: Qemu: $ git clone https://github.com/rivosinc/qemu.git $ cd qemu $ git switch -C dbltrp_v6 dev/cleger/dbltrp_v6 $ mkdir build && cd build $ ../configure --target-list=riscv64-softmmu $ make OpenSBI: $ git clone https://github.com/rivosinc/opensbi.git $ cd opensbi $ make O=build PLATFORM_RISCV_XLEN=64 PLATFORM=generic Linux: $ git clone https://github.com/rivosinc/linux.git $ cd linux $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 $ export ARCH=riscv $ make O=build defconfig $ ./script/config --file build/.config --enable RISCV_DBLTRP $ make O=build kvm-unit-tests: $ git clone https://github.com/clementleger/kvm-unit-tests.git $ cd kvm-unit-tests $ git switch -C dbltrp_v1 dev/cleger/dbltrp_v1 $ ./configure --arch=riscv64 --cross-prefix=$CROSS_COMPILE $ make You will also need kvmtool in your rootfs. Run with kvm-unit-test test as kernel: $ qemu-system-riscv64 \ -M virt \ -cpu rv64,ssdbltrp=true,smdbltrp=true \ -nographic \ -serial mon:stdio \ -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ -kernel kvm-unit-tests-dbltrp/riscv/sbi_dbltrp.flat ... [OpenSBI boot partially elided] Boot HART ISA Extensions : sscofpmf,sstc,zicntr,zihpm,zicboz,zicbom,sdtrig,svadu,ssdbltrp ... ########################################################################## # kvm-unit-tests ########################################################################## PASS: sbi: fwft: FWFT extension probing no error PASS: sbi: fwft: FWFT extension is present PASS: sbi: fwft: dbltrp: Get double trap enable feature value PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 PASS: sbi: fwft: dbltrp: Trapped twice allowed ok INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! sbi_trap_error: hart0: trap0: double trap handler failed (error -10) sbi_trap_error: hart0: trap0: mcause=0x0000000000000010 mtval=0x0000000000000000 sbi_trap_error: hart0: trap0: mtval2=0x0000000000000003 mtinst=0x0000000000000000 sbi_trap_error: hart0: trap0: mepc=0x00000000802000d8 mstatus=0x8000000a01006900 sbi_trap_error: hart0: trap0: ra=0x00000000802001fc sp=0x0000000080213e70 sbi_trap_error: hart0: trap0: gp=0x0000000000000000 tp=0x0000000080088000 sbi_trap_error: hart0: trap0: s0=0x0000000080213e80 s1=0x0000000000000001 sbi_trap_error: hart0: trap0: a0=0x0000000080213e80 a1=0x0000000080208193 sbi_trap_error: hart0: trap0: a2=0x000000008020dc20 a3=0x000000000000000f sbi_trap_error: hart0: trap0: a4=0x0000000080210cd8 a5=0x00000000802110d0 sbi_trap_error: hart0: trap0: a6=0x00000000802136e4 a7=0x0000000046574654 sbi_trap_error: hart0: trap0: s2=0x0000000080210cd9 s3=0x0000000000000000 sbi_trap_error: hart0: trap0: s4=0x0000000000000000 s5=0x0000000000000000 sbi_trap_error: hart0: trap0: s6=0x0000000000000000 s7=0x0000000000000001 sbi_trap_error: hart0: trap0: s8=0x0000000000002000 s9=0x0000000080083700 sbi_trap_error: hart0: trap0: s10=0x0000000000000000 s11=0x0000000000000000 sbi_trap_error: hart0: trap0: t0=0x0000000000000000 t1=0x0000000080213ed8 sbi_trap_error: hart0: trap0: t2=0x0000000000001000 t3=0x0000000080213ee0 sbi_trap_error: hart0: trap0: t4=0x0000000000000000 t5=0x000000008020f8d0 sbi_trap_error: hart0: trap0: t6=0x0000000000000000 Run with linux and kvm-unit-test test in kvm (testing VS-mode): $ qemu-system-riscv64 \ -M virt \ -cpu rv64,ssdbltrp=true,smdbltrp=true \ -nographic \ -serial mon:stdio \ -bios opensbi/build/platform/generic/firmware/fw_jump.bin \ -kernel linux/build/arch/riscv/boot/Image ... [Linux boot partially elided] [ 0.735079] riscv-dbltrp: Double trap handling registered ... $ lkvm run -k sbi_dbltrp.flat -m 128 -c 2 ########################################################################## # kvm-unit-tests ########################################################################## PASS: sbi: fwft: FWFT extension probing no error PASS: sbi: fwft: FWFT extension is present PASS: sbi: fwft: dbltrp: Get double trap enable feature value PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 0 PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 0 PASS: sbi: fwft: dbltrp: Double trap disabled, trap first time ok PASS: sbi: fwft: dbltrp: Set double trap enable feature value == 1 PASS: sbi: fwft: dbltrp: Get double trap enable feature value == 1 PASS: sbi: fwft: dbltrp: Trapped twice allowed ok INFO: sbi: fwft: dbltrp: Should generate a double trap and crash ! [ 51.939077] Guest double trap [ 51.939323] kvm [93]: VCPU exit error -95 [ 51.939683] kvm [93]: SEPC=0x802000d8 SSTATUS=0x200004520 HSTATUS=0x200200180 [ 51.939947] kvm [93]: SCAUSE=0x10 STVAL=0x0 HTVAL=0x3 HTINST=0x0 KVM_RUN failed: Operation not supported $ Testing Smbdbltrp can be done using gdb and trigger some trap. For instance, interrupt M-mode firmware at some point, set mstatus.mdt = 1 and corrupt some register to generate a NULL pointer exception. Link: https://github.com/riscv/riscv-isa-manual/commit/52a5742d5ab5a0792019033631b2035a493ad981 [1] Link: https://github.com/rivosinc/qemu/tree/dev/cleger/dbltrp_v7 [2] Link: https://github.com/rivosinc/linux/tree/dev/cleger/dbltrp_v1 [3] Link: https://github.com/clementleger/kvm-unit-tests/tree/dev/cleger/dbltrp_v1 [4] Link: https://lore.kernel.org/qemu-riscv/20241217062440.884261-1-frank.chang@sifive.com/ [5] --- V7: - Rebased on riscv-to-apply.next, on top of snrmi v10 series V6: - Simplify and fix write_henvcfg() masking by assigning the written value to henvcfg and mask the value to be written as well as clearing the upper part of henvcfgh upon writing. - Rebased on RNMI v9 series. V5: - Use 0 instead of false to set MSTATUS_MDT in helper_mnret() - Added explicit comments about henvcfg write mask being tricky. - Fixed a invalid menvcfg_mask in write_henvcfgh V4: - Remove DTE from sstatus_v1_10_mask variable and add specific if for DTE masking where it's used. - Use mstatus_hs.sdt field rather than setting DTE to 0 in riscv_do_cpu_interrupt(). - Add a fix for henvcfg value which was incorrectly set after changing menvcfg - Remove useless ext_ssdbltrp check in riscv_env_smode_dbltrp_enabled(). - Remove useless mstatus clear in write_mstatus(). - Add proper handling of SDT writing to vsstatus. - Add clearing of vsstatus//mstatus SDT field when DTE is disabled. - Fix wrong value being written for MDT/MIE in write_mstatush(). - Rebased on Frank Snrnmi v7 V3: - Fix spec version from 1.12 to 1.13 for Smdbltrp and Ssdbltrp - Add better comments for dte/sdt computation in riscv_cpu_do_interrupt(). - Move some CSR related changes to the CSRs related commits. V2: - Squashed commits that added ext_s{s|m}dbltrp as suggested by Daniel Clément Léger (9): target/riscv: Fix henvcfg potentially containing stale bits target/riscv: Add Ssdbltrp CSRs handling target/riscv: Implement Ssdbltrp sret, mret and mnret behavior target/riscv: Implement Ssdbltrp exception handling target/riscv: Add Ssdbltrp ISA extension enable switch target/riscv: Add Smdbltrp CSRs handling target/riscv: Implement Smdbltrp sret, mret and mnret behavior target/riscv: Implement Smdbltrp behavior target/riscv: Add Smdbltrp ISA extension enable switch target/riscv/cpu.c | 9 ++- target/riscv/cpu.h | 1 + target/riscv/cpu_bits.h | 8 +++ target/riscv/cpu_cfg.h | 2 + target/riscv/cpu_helper.c | 115 +++++++++++++++++++++++++++++++------- target/riscv/csr.c | 95 ++++++++++++++++++++++++++----- target/riscv/op_helper.c | 47 +++++++++++++++- 7 files changed, 239 insertions(+), 38 deletions(-)