| Message ID | 20230307023946.14516-1-xin3.li@intel.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | x86: enable FRED for x86-64 | expand |
We tested the v5 FRED patch set on the Intel Simics® Simulator and a machine with a 7th Intel(R) Core(TM) CPU. Following are the Kselftest results on X86-64. +--------------------------------------------+-------+-------+-------+-------+ | Config | Pass | Fail | Skip | Hang | +--------------------------------------------+-------+-------+-------+-------+ | the 7th Intel(R) Core(TM) CPU | 3078 | 458 | 734 | 5 | | 6.3.0-rc1+ | | | | | +--------------------------------------------+-------+-------+-------+-------+ | the 7th Intel(R) Core(TM) CPU | 3078 | 458 | 734 | 5 | | 6.3.0-rc1+ w/ FRED patch set | | | | | +--------------------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/o FRED model | 1888 | 271 | 2105 | 11 | | 6.3.0-rc1+ | | | | | +--------------------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/o FRED model | 1888 | 271 | 2105 | 11 | | 6.3.0-rc1+ w/ FRED patch set | | | | | +--------------------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ FRED model | 1889 | 270 | 2105 | 11 | | 6.3.0-rc1+ | | | | | +--------------------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ FRED model | 1889 | 270 | 2105 | 11 | | 6.3.0-rc1+ w/ FRED patch set FRED disabled | | | | | +--------------------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ FRED model | 1888 | 270 | 2105 | 12 | | 6.3.0-rc1+ w/ FRED patch set | | | | | +--------------------------------------------+-------+-------+-------+-------+ The following issues are seen in this round of test. +----------------+----------------+----------------+----------------+ | | x86:test_ | bpf:test_progs | x86:sysret | | | vsyscall_32 | | _rip_64 | +----------------+----------------+----------------+----------------+ | the 7th | | | | | Intel(R) | FAIL | FAIL | PASS | | Core(TM) CPU | | | | | 6.3.0-rc1+ | | | | +----------------+----------------+----------------+----------------+ | the 7th | | | | | Intel(R) | | | | | Core(TM) CPU | FAIL | FAIL | PASS | | 6.3.0-rc1+ w/ | | | | | FRED patch set | | | | +----------------+----------------+----------------+----------------+ | Intel Simics® | | | | | Simulator w/o | FAIL | FAIL | PASS | | FRED model | | | | | 6.3.0-rc1+ | | | | +----------------+----------------+----------------+----------------+ | Intel Simics® | | | | | Simulator w/o | | | | | FRED model | FAIL | FAIL | PASS | | 6.3.0-rc1+ w/ | | | | | FRED patch set | | | | +----------------+----------------+----------------+----------------+ | Intel Simics® | | | | | Simulator w/ | PASS | FAIL | PASS | | FRED model | | | | | 6.3.0-rc1+ | | | | +----------------+----------------+----------------+----------------+ | Intel Simics® | | | | | Simulator w/ | | | | | FRED model | PASS | FAIL | PASS | | 6.3.0-rc1+ w/ | | | | | FRED patch set | | | | | FRED disabled | | | | +----------------+----------------+----------------+----------------+ | Intel Simics® | | | | | Simulator w/ | | | | | FRED model | PASS | HANG | FAIL | | 6.3.0-rc1+ w/ | | | | | FRED patch set | | | | +----------------+----------------+----------------+----------------+ The test "x86:sysret_rip_64" is NOT a valid test on FRED, and there is a fix from Ammar Faizi after we discussed it in the LKML. The test "bpf:test_progs" is still in investigation. The "x86:test_vsyscall_32" is a regression since the v3 FRED patch set. Thanks --Shan On Mon, 2023-03-06 at 18:39 -0800, Xin Li wrote: > This patch set enables FRED for x86-64. > > The Intel flexible return and event delivery (FRED) architecture defines > simple > new transitions that change privilege level (ring transitions). The FRED > architecture was designed with the following goals: > 1) Improve overall performance and response time by replacing event delivery > through the interrupt descriptor table (IDT event delivery) and event return > by > the IRET instruction with lower latency transitions. > 2) Improve software robustness by ensuring that event delivery establishes the > full supervisor context and that event return establishes the full user > context. > > The new transitions defined by the FRED architecture are FRED event delivery > and, > for returning from events, two FRED return instructions. FRED event delivery > can > effect a transition from ring 3 to ring 0, but it is used also to deliver > events > incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 > to > ring 3, while the other (ERETS) returns while remaining in ring 0. > > Search for the latest FRED spec in most search engines with this search > pattern: > > site:intel.com FRED (flexible return and event delivery) specification > > As of now there is no publicly avaiable CPU supporting FRED, thus the Intel > Simics® Simulator is used as software development and testing vehicles. And > it can be downloaded from: > > https://www.intel.com/content/www/us/en/developer/articles/tool/simics-simulator.html > > To enable FRED, the Simics package 8112 QSP-CPU needs to be installed with CPU > model configured as: > $cpu_comp_class = "x86-experimental-fred" > > Longer term, we should refactor common code shared by FRED and IDT into common > shared files, and contain IDT code using a new config CONFIG_X86_IDT. > > Changes since v4: > * Rebased against v6.3-rc1. > * Do NOT use the term "injection", which in the KVM context means to > reinject an event into the guest (Sean Christopherson). > * Add the explanation of why to execute "int $2" to invoke the NMI handler > in NMI caused VM exits (Sean Christopherson). > * Use cs/ss instead of csx/ssx when initializing the pt_regs structure > for calling external_interrupt(), otherwise it breaks i386 build. > > Changes since v3: > * Call external_interrupt() to handle IRQ in IRQ caused VM exits. > * Execute "int $2" to handle NMI in NMI caused VM exits. > * Rename csl/ssl of the pt_regs structure to csx/ssx (x for extended) > (Andrew Cooper). > > Changes since v2: > * Improve comments for changes in arch/x86/include/asm/idtentry.h. > > Changes since v1: > * call irqentry_nmi_{enter,exit}() in both IDT and FRED debug fault kernel > handler (Peter Zijlstra). > * Initialize a FRED exception handler to fred_bad_event() instead of NULL > if no FRED handler defined for an exception vector (Peter Zijlstra). > * Push calling irqentry_{enter,exit}() and instrumentation_{begin,end}() > down into individual FRED exception handlers, instead of in the dispatch > framework (Peter Zijlstra). > > > H. Peter Anvin (Intel) (24): > x86/traps: let common_interrupt() handle IRQ_MOVE_CLEANUP_VECTOR > x86/traps: add a system interrupt table for system interrupt dispatch > x86/traps: add external_interrupt() to dispatch external interrupts > x86/cpufeature: add the cpu feature bit for FRED > x86/opcode: add ERETU, ERETS instructions to x86-opcode-map > x86/objtool: teach objtool about ERETU and ERETS > x86/cpu: add X86_CR4_FRED macro > x86/fred: add Kconfig option for FRED (CONFIG_X86_FRED) > x86/fred: if CONFIG_X86_FRED is disabled, disable FRED support > x86/cpu: add MSR numbers for FRED configuration > x86/fred: header file with FRED definitions > x86/fred: make unions for the cs and ss fields in struct pt_regs > x86/fred: reserve space for the FRED stack frame > x86/fred: add a page fault entry stub for FRED > x86/fred: add a debug fault entry stub for FRED > x86/fred: add a NMI entry stub for FRED > x86/fred: FRED entry/exit and dispatch code > x86/fred: FRED initialization code > x86/fred: update MSR_IA32_FRED_RSP0 during task switch > x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is > enabled > x86/fred: disallow the swapgs instruction when FRED is enabled > x86/fred: no ESPFIX needed when FRED is enabled > x86/fred: allow single-step trap and NMI when starting a new thread > x86/fred: allow FRED systems to use interrupt vectors 0x10-0x1f > > Xin Li (10): > x86/traps: add install_system_interrupt_handler() > x86/traps: export external_interrupt() for VMX IRQ reinjection > x86/fred: header file for event types > x86/fred: add a machine check entry stub for FRED > x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user > x86/ia32: do not modify the DPL bits for a null selector > x86/fred: allow dynamic stack frame size > x86/fred: disable FRED by default in its early stage > KVM: x86/vmx: call external_interrupt() to handle IRQ in IRQ caused VM > exits > KVM: x86/vmx: execute "int $2" to handle NMI in NMI caused VM exits > when FRED is enabled > > .../admin-guide/kernel-parameters.txt | 4 + > arch/x86/Kconfig | 9 + > arch/x86/entry/Makefile | 5 +- > arch/x86/entry/entry_32.S | 2 +- > arch/x86/entry/entry_64.S | 5 + > arch/x86/entry/entry_64_fred.S | 59 +++++ > arch/x86/entry/entry_fred.c | 234 ++++++++++++++++++ > arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- > arch/x86/include/asm/cpufeatures.h | 1 + > arch/x86/include/asm/disabled-features.h | 8 +- > arch/x86/include/asm/entry-common.h | 3 + > arch/x86/include/asm/event-type.h | 17 ++ > arch/x86/include/asm/extable_fixup_types.h | 4 +- > arch/x86/include/asm/fred.h | 131 ++++++++++ > arch/x86/include/asm/idtentry.h | 76 +++++- > arch/x86/include/asm/irq.h | 5 + > arch/x86/include/asm/irq_vectors.h | 15 +- > arch/x86/include/asm/msr-index.h | 13 +- > arch/x86/include/asm/processor.h | 12 +- > arch/x86/include/asm/ptrace.h | 36 ++- > arch/x86/include/asm/switch_to.h | 10 +- > arch/x86/include/asm/thread_info.h | 35 +-- > arch/x86/include/asm/traps.h | 13 + > arch/x86/include/asm/vmx.h | 17 +- > arch/x86/include/uapi/asm/processor-flags.h | 2 + > arch/x86/kernel/Makefile | 1 + > arch/x86/kernel/apic/apic.c | 11 +- > arch/x86/kernel/apic/vector.c | 8 +- > arch/x86/kernel/cpu/acrn.c | 7 +- > arch/x86/kernel/cpu/common.c | 88 ++++--- > arch/x86/kernel/cpu/mce/core.c | 11 + > arch/x86/kernel/cpu/mshyperv.c | 22 +- > arch/x86/kernel/espfix_64.c | 8 + > arch/x86/kernel/fred.c | 73 ++++++ > arch/x86/kernel/head_32.S | 3 +- > arch/x86/kernel/idt.c | 6 +- > arch/x86/kernel/irq.c | 6 +- > arch/x86/kernel/irqinit.c | 7 +- > arch/x86/kernel/kvm.c | 4 +- > arch/x86/kernel/nmi.c | 28 +++ > arch/x86/kernel/process.c | 5 + > arch/x86/kernel/process_64.c | 21 +- > arch/x86/kernel/signal_32.c | 21 +- > arch/x86/kernel/traps.c | 175 +++++++++++-- > arch/x86/kvm/vmx/vmx.c | 33 ++- > arch/x86/lib/x86-opcode-map.txt | 2 +- > arch/x86/mm/extable.c | 28 +++ > arch/x86/mm/fault.c | 20 +- > drivers/xen/events/events_base.c | 5 +- > kernel/fork.c | 6 + > tools/arch/x86/include/asm/cpufeatures.h | 1 + > .../arch/x86/include/asm/disabled-features.h | 8 +- > tools/arch/x86/include/asm/msr-index.h | 13 +- > tools/arch/x86/lib/x86-opcode-map.txt | 2 +- > tools/objtool/arch/x86/decode.c | 19 +- > 55 files changed, 1185 insertions(+), 175 deletions(-) > create mode 100644 arch/x86/entry/entry_64_fred.S > create mode 100644 arch/x86/entry/entry_fred.c > create mode 100644 arch/x86/include/asm/event-type.h > create mode 100644 arch/x86/include/asm/fred.h > create mode 100644 arch/x86/kernel/fred.c >
> The following issues are seen in this round of test. > +----------------+----------------+----------------+----------------+ > | | x86:test_ | bpf:test_progs | x86:sysret | > | | vsyscall_32 | | _rip_64 | > +----------------+----------------+----------------+----------------+ > | the 7th | | | | > | Intel(R) | FAIL | FAIL | PASS | > | Core(TM) CPU | | | | > | 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > | the 7th | | | | > | Intel(R) | | | | > | Core(TM) CPU | FAIL | FAIL | PASS | > | 6.3.0-rc1+ w/ | | | | > | FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > | Intel Simics® | | | | > | Simulator w/o | FAIL | FAIL | PASS | > | FRED model | | | | > | 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > | Intel Simics® | | | | > | Simulator w/o | | | | > | FRED model | FAIL | FAIL | PASS | > | 6.3.0-rc1+ w/ | | | | > | FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > | Intel Simics® | | | | > | Simulator w/ | PASS | FAIL | PASS | > | FRED model | | | | > | 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > | Intel Simics® | | | | > | Simulator w/ | | | | > | FRED model | PASS | FAIL | PASS | > | 6.3.0-rc1+ w/ | | | | > | FRED patch set | | | | > | FRED disabled | | | | > +----------------+----------------+----------------+----------------+ > | Intel Simics® | | | | > | Simulator w/ | | | | > | FRED model | PASS | HANG | FAIL | > | 6.3.0-rc1+ w/ | | | | > | FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > > The "x86:test_vsyscall_32" is a regression since the v3 FRED patch set. The "x86:test_vsyscall_32" test passes on the Simics FRED model, no matter whether FRED is enabled or not, because the Simics FRED model has the RDPID instruction support. While on a Simics non-FRED model or the test bare metal machine, which don't have the RDPID instruction support, the test reads CPU ID from the GDT_ENTRY_CPUNODE entry, thus it fails due to: https://lore.kernel.org/lkml/20230311084824.2340-1-xin3.li@intel.com/ Thanks! Xin
We wanted to check whether there are KVM regressions with the v5 FRED patch set, and had a round of Kselftest on KVM guests. Following are the results on X86-64. +--------------------------------+-------+-------+-------+-------+ | Config | Pass | Fail | Skip | Hang | +--------------------------------+-------+-------+-------+-------+ | the 7th Intel(R) Core(TM) CPU | | | | | | | host 6.3.0-rc1+ w/ FRED | 2720 | 403 | 689 | 9 | | patch set FRED disabled | | | | | | | guest 6.3.0-rc1+ | | | | | +--------------------------------+-------+-------+-------+-------+ | the 7th Intel(R) Core(TM) CPU | | | | | | | host 6.3.0-rc1+ w/ FRED | 2720 | 403 | 689 | 9 | | patch set | guest 6.3.0-rc1+ | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/o | | | | | | FRED model | host 6.3.0-rc1+ | | 1403 | 277 | 2127 | 14 | | guest 6.3.0-rc1+ | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/o | | | | | | FRED model | host 6.3.0-rc1+ | | | | | | w/ FRED patch set | guest | 1403 | 277 | 2127 | 14 | | 6.3.0-rc1+ w/ FRED patch set | | | | | | FRED disabled | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/o | | | | | | FRED model | host 6.3.0-rc1+ | 1403 | 277 | 2127 | 14 | | w/ FRED patch set | guest | | | | | | 6.3.0-rc1+ w/ FRED patch set | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model + host 6.3.0-rc1+ | | 1404 | 276 | 2127 | 14 | | guest 6.3.0-rc1+ w/ FRED patch | | | | | | set | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model | host 6.3.0-rc1+ | 1404 | 276 | 2127 | 14 | | w/ FRED patch set FRED | | | | | | disabled | guest 6.3.0-rc1+ | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model | host 6.3.0-rc1+ | | | | | | w/ FRED patch set FRED | 1404 | 276 | 2127 | 14 | | disabled | guest 6.3.0-rc1+ w/ | | | | | | FRED patch set | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model | host 6.3.0-rc1+ | 1404 | 276 | 2127 | 14 | | w/ FRED patch set | guest | | | | | | 6.3.0-rc1+ | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model | host 6.3.0-rc1+ | | | | | | w/ FRED patch set | guest | 1404 | 276 | 2127 | 14 | | 6.3.0-rc1+ w/ FRED patch set | | | | | | FRED disabled | | | | | +--------------------------------+-------+-------+-------+-------+ | Intel Simics® Simulator w/ | | | | | | FRED model | host 6.3.0-rc1+ | 1404 | 276 | 2127 | 14 | | w/ FRED patch set | guest | | | | | | 6.3.0-rc1+ w/ FRED patch set | | | | | +--------------------------------+-------+-------+-------+-------+ The Simics FRED model has one more passed case, which is x86:test_vsyscall_32, due to https://lore.kernel.org/lkml/20230311084824.2340-1-xin3.li@intel.com/. Thanks --Shan On Sat, 2023-03-11 at 09:58 +0000, Kang, Shan wrote: > We tested the v5 FRED patch set on the Intel Simics® Simulator and a machine > with a 7th Intel(R) Core(TM) CPU. > > Following are the Kselftest results on X86-64. > +--------------------------------------------+-------+-------+-------+-------+ > > Config | Pass | Fail | Skip | Hang | > +--------------------------------------------+-------+-------+-------+-------+ > > the 7th Intel(R) Core(TM) CPU | 3078 | 458 | 734 | 5 | > > 6.3.0-rc1+ | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > the 7th Intel(R) Core(TM) CPU | 3078 | 458 | 734 | 5 | > > 6.3.0-rc1+ w/ FRED patch set | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > Intel Simics® Simulator w/o FRED model | 1888 | 271 | 2105 | 11 | > > 6.3.0-rc1+ | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > Intel Simics® Simulator w/o FRED model | 1888 | 271 | 2105 | 11 | > > 6.3.0-rc1+ w/ FRED patch set | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > Intel Simics® Simulator w/ FRED model | 1889 | 270 | 2105 | 11 | > > 6.3.0-rc1+ | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > Intel Simics® Simulator w/ FRED model | 1889 | 270 | 2105 | 11 | > > 6.3.0-rc1+ w/ FRED patch set FRED disabled | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > Intel Simics® Simulator w/ FRED model | 1888 | 270 | 2105 | 12 | > > 6.3.0-rc1+ w/ FRED patch set | | | | | > +--------------------------------------------+-------+-------+-------+-------+ > > The following issues are seen in this round of test. > +----------------+----------------+----------------+----------------+ > > | x86:test_ | bpf:test_progs | x86:sysret | > > | vsyscall_32 | | _rip_64 | > +----------------+----------------+----------------+----------------+ > > the 7th | | | | > > Intel(R) | FAIL | FAIL | PASS | > > Core(TM) CPU | | | | > > 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > > the 7th | | | | > > Intel(R) | | | | > > Core(TM) CPU | FAIL | FAIL | PASS | > > 6.3.0-rc1+ w/ | | | | > > FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > > Intel Simics® | | | | > > Simulator w/o | FAIL | FAIL | PASS | > > FRED model | | | | > > 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > > Intel Simics® | | | | > > Simulator w/o | | | | > > FRED model | FAIL | FAIL | PASS | > > 6.3.0-rc1+ w/ | | | | > > FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > > Intel Simics® | | | | > > Simulator w/ | PASS | FAIL | PASS | > > FRED model | | | | > > 6.3.0-rc1+ | | | | > +----------------+----------------+----------------+----------------+ > > Intel Simics® | | | | > > Simulator w/ | | | | > > FRED model | PASS | FAIL | PASS | > > 6.3.0-rc1+ w/ | | | | > > FRED patch set | | | | > > FRED disabled | | | | > +----------------+----------------+----------------+----------------+ > > Intel Simics® | | | | > > Simulator w/ | | | | > > FRED model | PASS | HANG | FAIL | > > 6.3.0-rc1+ w/ | | | | > > FRED patch set | | | | > +----------------+----------------+----------------+----------------+ > > The test "x86:sysret_rip_64" is NOT a valid test on FRED, and there is a fix > from Ammar Faizi after we discussed it in the LKML. > > The test "bpf:test_progs" is still in investigation. > > The "x86:test_vsyscall_32" is a regression since the v3 FRED patch set. > > Thanks > --Shan > > On Mon, 2023-03-06 at 18:39 -0800, Xin Li wrote: > > This patch set enables FRED for x86-64. > > > > The Intel flexible return and event delivery (FRED) architecture defines > > simple > > new transitions that change privilege level (ring transitions). The FRED > > architecture was designed with the following goals: > > 1) Improve overall performance and response time by replacing event delivery > > through the interrupt descriptor table (IDT event delivery) and event return > > by > > the IRET instruction with lower latency transitions. > > 2) Improve software robustness by ensuring that event delivery establishes > > the > > full supervisor context and that event return establishes the full user > > context. > > > > The new transitions defined by the FRED architecture are FRED event delivery > > and, > > for returning from events, two FRED return instructions. FRED event delivery > > can > > effect a transition from ring 3 to ring 0, but it is used also to deliver > > events > > incident to ring 0. One FRED instruction (ERETU) effects a return from ring > > 0 > > to > > ring 3, while the other (ERETS) returns while remaining in ring 0. > > > > Search for the latest FRED spec in most search engines with this search > > pattern: > > > > site:intel.com FRED (flexible return and event delivery) specification > > > > As of now there is no publicly avaiable CPU supporting FRED, thus the Intel > > Simics® Simulator is used as software development and testing vehicles. And > > it can be downloaded from: > > > > https://www.intel.com/content/www/us/en/developer/articles/tool/simics-simulator.html > > > > To enable FRED, the Simics package 8112 QSP-CPU needs to be installed with > > CPU > > model configured as: > > $cpu_comp_class = "x86-experimental-fred" > > > > Longer term, we should refactor common code shared by FRED and IDT into > > common > > shared files, and contain IDT code using a new config CONFIG_X86_IDT. > > > > Changes since v4: > > * Rebased against v6.3-rc1. > > * Do NOT use the term "injection", which in the KVM context means to > > reinject an event into the guest (Sean Christopherson). > > * Add the explanation of why to execute "int $2" to invoke the NMI handler > > in NMI caused VM exits (Sean Christopherson). > > * Use cs/ss instead of csx/ssx when initializing the pt_regs structure > > for calling external_interrupt(), otherwise it breaks i386 build. > > > > Changes since v3: > > * Call external_interrupt() to handle IRQ in IRQ caused VM exits. > > * Execute "int $2" to handle NMI in NMI caused VM exits. > > * Rename csl/ssl of the pt_regs structure to csx/ssx (x for extended) > > (Andrew Cooper). > > > > Changes since v2: > > * Improve comments for changes in arch/x86/include/asm/idtentry.h. > > > > Changes since v1: > > * call irqentry_nmi_{enter,exit}() in both IDT and FRED debug fault kernel > > handler (Peter Zijlstra). > > * Initialize a FRED exception handler to fred_bad_event() instead of NULL > > if no FRED handler defined for an exception vector (Peter Zijlstra). > > * Push calling irqentry_{enter,exit}() and instrumentation_{begin,end}() > > down into individual FRED exception handlers, instead of in the dispatch > > framework (Peter Zijlstra). > > > > > > H. Peter Anvin (Intel) (24): > > x86/traps: let common_interrupt() handle IRQ_MOVE_CLEANUP_VECTOR > > x86/traps: add a system interrupt table for system interrupt dispatch > > x86/traps: add external_interrupt() to dispatch external interrupts > > x86/cpufeature: add the cpu feature bit for FRED > > x86/opcode: add ERETU, ERETS instructions to x86-opcode-map > > x86/objtool: teach objtool about ERETU and ERETS > > x86/cpu: add X86_CR4_FRED macro > > x86/fred: add Kconfig option for FRED (CONFIG_X86_FRED) > > x86/fred: if CONFIG_X86_FRED is disabled, disable FRED support > > x86/cpu: add MSR numbers for FRED configuration > > x86/fred: header file with FRED definitions > > x86/fred: make unions for the cs and ss fields in struct pt_regs > > x86/fred: reserve space for the FRED stack frame > > x86/fred: add a page fault entry stub for FRED > > x86/fred: add a debug fault entry stub for FRED > > x86/fred: add a NMI entry stub for FRED > > x86/fred: FRED entry/exit and dispatch code > > x86/fred: FRED initialization code > > x86/fred: update MSR_IA32_FRED_RSP0 during task switch > > x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is > > enabled > > x86/fred: disallow the swapgs instruction when FRED is enabled > > x86/fred: no ESPFIX needed when FRED is enabled > > x86/fred: allow single-step trap and NMI when starting a new thread > > x86/fred: allow FRED systems to use interrupt vectors 0x10-0x1f > > > > Xin Li (10): > > x86/traps: add install_system_interrupt_handler() > > x86/traps: export external_interrupt() for VMX IRQ reinjection > > x86/fred: header file for event types > > x86/fred: add a machine check entry stub for FRED > > x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user > > x86/ia32: do not modify the DPL bits for a null selector > > x86/fred: allow dynamic stack frame size > > x86/fred: disable FRED by default in its early stage > > KVM: x86/vmx: call external_interrupt() to handle IRQ in IRQ caused VM > > exits > > KVM: x86/vmx: execute "int $2" to handle NMI in NMI caused VM exits > > when FRED is enabled > > > > .../admin-guide/kernel-parameters.txt | 4 + > > arch/x86/Kconfig | 9 + > > arch/x86/entry/Makefile | 5 +- > > arch/x86/entry/entry_32.S | 2 +- > > arch/x86/entry/entry_64.S | 5 + > > arch/x86/entry/entry_64_fred.S | 59 +++++ > > arch/x86/entry/entry_fred.c | 234 ++++++++++++++++++ > > arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- > > arch/x86/include/asm/cpufeatures.h | 1 + > > arch/x86/include/asm/disabled-features.h | 8 +- > > arch/x86/include/asm/entry-common.h | 3 + > > arch/x86/include/asm/event-type.h | 17 ++ > > arch/x86/include/asm/extable_fixup_types.h | 4 +- > > arch/x86/include/asm/fred.h | 131 ++++++++++ > > arch/x86/include/asm/idtentry.h | 76 +++++- > > arch/x86/include/asm/irq.h | 5 + > > arch/x86/include/asm/irq_vectors.h | 15 +- > > arch/x86/include/asm/msr-index.h | 13 +- > > arch/x86/include/asm/processor.h | 12 +- > > arch/x86/include/asm/ptrace.h | 36 ++- > > arch/x86/include/asm/switch_to.h | 10 +- > > arch/x86/include/asm/thread_info.h | 35 +-- > > arch/x86/include/asm/traps.h | 13 + > > arch/x86/include/asm/vmx.h | 17 +- > > arch/x86/include/uapi/asm/processor-flags.h | 2 + > > arch/x86/kernel/Makefile | 1 + > > arch/x86/kernel/apic/apic.c | 11 +- > > arch/x86/kernel/apic/vector.c | 8 +- > > arch/x86/kernel/cpu/acrn.c | 7 +- > > arch/x86/kernel/cpu/common.c | 88 ++++--- > > arch/x86/kernel/cpu/mce/core.c | 11 + > > arch/x86/kernel/cpu/mshyperv.c | 22 +- > > arch/x86/kernel/espfix_64.c | 8 + > > arch/x86/kernel/fred.c | 73 ++++++ > > arch/x86/kernel/head_32.S | 3 +- > > arch/x86/kernel/idt.c | 6 +- > > arch/x86/kernel/irq.c | 6 +- > > arch/x86/kernel/irqinit.c | 7 +- > > arch/x86/kernel/kvm.c | 4 +- > > arch/x86/kernel/nmi.c | 28 +++ > > arch/x86/kernel/process.c | 5 + > > arch/x86/kernel/process_64.c | 21 +- > > arch/x86/kernel/signal_32.c | 21 +- > > arch/x86/kernel/traps.c | 175 +++++++++++-- > > arch/x86/kvm/vmx/vmx.c | 33 ++- > > arch/x86/lib/x86-opcode-map.txt | 2 +- > > arch/x86/mm/extable.c | 28 +++ > > arch/x86/mm/fault.c | 20 +- > > drivers/xen/events/events_base.c | 5 +- > > kernel/fork.c | 6 + > > tools/arch/x86/include/asm/cpufeatures.h | 1 + > > .../arch/x86/include/asm/disabled-features.h | 8 +- > > tools/arch/x86/include/asm/msr-index.h | 13 +- > > tools/arch/x86/lib/x86-opcode-map.txt | 2 +- > > tools/objtool/arch/x86/decode.c | 19 +- > > 55 files changed, 1185 insertions(+), 175 deletions(-) > > create mode 100644 arch/x86/entry/entry_64_fred.S > > create mode 100644 arch/x86/entry/entry_fred.c > > create mode 100644 arch/x86/include/asm/event-type.h > > create mode 100644 arch/x86/include/asm/fred.h > > create mode 100644 arch/x86/kernel/fred.c > >
This patch set enables FRED for x86-64. The Intel flexible return and event delivery (FRED) architecture defines simple new transitions that change privilege level (ring transitions). The FRED architecture was designed with the following goals: 1) Improve overall performance and response time by replacing event delivery through the interrupt descriptor table (IDT event delivery) and event return by the IRET instruction with lower latency transitions. 2) Improve software robustness by ensuring that event delivery establishes the full supervisor context and that event return establishes the full user context. The new transitions defined by the FRED architecture are FRED event delivery and, for returning from events, two FRED return instructions. FRED event delivery can effect a transition from ring 3 to ring 0, but it is used also to deliver events incident to ring 0. One FRED instruction (ERETU) effects a return from ring 0 to ring 3, while the other (ERETS) returns while remaining in ring 0. Search for the latest FRED spec in most search engines with this search pattern: site:intel.com FRED (flexible return and event delivery) specification As of now there is no publicly avaiable CPU supporting FRED, thus the Intel Simics® Simulator is used as software development and testing vehicles. And it can be downloaded from: https://www.intel.com/content/www/us/en/developer/articles/tool/simics-simulator.html To enable FRED, the Simics package 8112 QSP-CPU needs to be installed with CPU model configured as: $cpu_comp_class = "x86-experimental-fred" Longer term, we should refactor common code shared by FRED and IDT into common shared files, and contain IDT code using a new config CONFIG_X86_IDT. Changes since v4: * Rebased against v6.3-rc1. * Do NOT use the term "injection", which in the KVM context means to reinject an event into the guest (Sean Christopherson). * Add the explanation of why to execute "int $2" to invoke the NMI handler in NMI caused VM exits (Sean Christopherson). * Use cs/ss instead of csx/ssx when initializing the pt_regs structure for calling external_interrupt(), otherwise it breaks i386 build. Changes since v3: * Call external_interrupt() to handle IRQ in IRQ caused VM exits. * Execute "int $2" to handle NMI in NMI caused VM exits. * Rename csl/ssl of the pt_regs structure to csx/ssx (x for extended) (Andrew Cooper). Changes since v2: * Improve comments for changes in arch/x86/include/asm/idtentry.h. Changes since v1: * call irqentry_nmi_{enter,exit}() in both IDT and FRED debug fault kernel handler (Peter Zijlstra). * Initialize a FRED exception handler to fred_bad_event() instead of NULL if no FRED handler defined for an exception vector (Peter Zijlstra). * Push calling irqentry_{enter,exit}() and instrumentation_{begin,end}() down into individual FRED exception handlers, instead of in the dispatch framework (Peter Zijlstra). H. Peter Anvin (Intel) (24): x86/traps: let common_interrupt() handle IRQ_MOVE_CLEANUP_VECTOR x86/traps: add a system interrupt table for system interrupt dispatch x86/traps: add external_interrupt() to dispatch external interrupts x86/cpufeature: add the cpu feature bit for FRED x86/opcode: add ERETU, ERETS instructions to x86-opcode-map x86/objtool: teach objtool about ERETU and ERETS x86/cpu: add X86_CR4_FRED macro x86/fred: add Kconfig option for FRED (CONFIG_X86_FRED) x86/fred: if CONFIG_X86_FRED is disabled, disable FRED support x86/cpu: add MSR numbers for FRED configuration x86/fred: header file with FRED definitions x86/fred: make unions for the cs and ss fields in struct pt_regs x86/fred: reserve space for the FRED stack frame x86/fred: add a page fault entry stub for FRED x86/fred: add a debug fault entry stub for FRED x86/fred: add a NMI entry stub for FRED x86/fred: FRED entry/exit and dispatch code x86/fred: FRED initialization code x86/fred: update MSR_IA32_FRED_RSP0 during task switch x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is enabled x86/fred: disallow the swapgs instruction when FRED is enabled x86/fred: no ESPFIX needed when FRED is enabled x86/fred: allow single-step trap and NMI when starting a new thread x86/fred: allow FRED systems to use interrupt vectors 0x10-0x1f Xin Li (10): x86/traps: add install_system_interrupt_handler() x86/traps: export external_interrupt() for VMX IRQ reinjection x86/fred: header file for event types x86/fred: add a machine check entry stub for FRED x86/fred: fixup fault on ERETU by jumping to fred_entrypoint_user x86/ia32: do not modify the DPL bits for a null selector x86/fred: allow dynamic stack frame size x86/fred: disable FRED by default in its early stage KVM: x86/vmx: call external_interrupt() to handle IRQ in IRQ caused VM exits KVM: x86/vmx: execute "int $2" to handle NMI in NMI caused VM exits when FRED is enabled .../admin-guide/kernel-parameters.txt | 4 + arch/x86/Kconfig | 9 + arch/x86/entry/Makefile | 5 +- arch/x86/entry/entry_32.S | 2 +- arch/x86/entry/entry_64.S | 5 + arch/x86/entry/entry_64_fred.S | 59 +++++ arch/x86/entry/entry_fred.c | 234 ++++++++++++++++++ arch/x86/entry/vsyscall/vsyscall_64.c | 2 +- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/include/asm/disabled-features.h | 8 +- arch/x86/include/asm/entry-common.h | 3 + arch/x86/include/asm/event-type.h | 17 ++ arch/x86/include/asm/extable_fixup_types.h | 4 +- arch/x86/include/asm/fred.h | 131 ++++++++++ arch/x86/include/asm/idtentry.h | 76 +++++- arch/x86/include/asm/irq.h | 5 + arch/x86/include/asm/irq_vectors.h | 15 +- arch/x86/include/asm/msr-index.h | 13 +- arch/x86/include/asm/processor.h | 12 +- arch/x86/include/asm/ptrace.h | 36 ++- arch/x86/include/asm/switch_to.h | 10 +- arch/x86/include/asm/thread_info.h | 35 +-- arch/x86/include/asm/traps.h | 13 + arch/x86/include/asm/vmx.h | 17 +- arch/x86/include/uapi/asm/processor-flags.h | 2 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/apic/apic.c | 11 +- arch/x86/kernel/apic/vector.c | 8 +- arch/x86/kernel/cpu/acrn.c | 7 +- arch/x86/kernel/cpu/common.c | 88 ++++--- arch/x86/kernel/cpu/mce/core.c | 11 + arch/x86/kernel/cpu/mshyperv.c | 22 +- arch/x86/kernel/espfix_64.c | 8 + arch/x86/kernel/fred.c | 73 ++++++ arch/x86/kernel/head_32.S | 3 +- arch/x86/kernel/idt.c | 6 +- arch/x86/kernel/irq.c | 6 +- arch/x86/kernel/irqinit.c | 7 +- arch/x86/kernel/kvm.c | 4 +- arch/x86/kernel/nmi.c | 28 +++ arch/x86/kernel/process.c | 5 + arch/x86/kernel/process_64.c | 21 +- arch/x86/kernel/signal_32.c | 21 +- arch/x86/kernel/traps.c | 175 +++++++++++-- arch/x86/kvm/vmx/vmx.c | 33 ++- arch/x86/lib/x86-opcode-map.txt | 2 +- arch/x86/mm/extable.c | 28 +++ arch/x86/mm/fault.c | 20 +- drivers/xen/events/events_base.c | 5 +- kernel/fork.c | 6 + tools/arch/x86/include/asm/cpufeatures.h | 1 + .../arch/x86/include/asm/disabled-features.h | 8 +- tools/arch/x86/include/asm/msr-index.h | 13 +- tools/arch/x86/lib/x86-opcode-map.txt | 2 +- tools/objtool/arch/x86/decode.c | 19 +- 55 files changed, 1185 insertions(+), 175 deletions(-) create mode 100644 arch/x86/entry/entry_64_fred.S create mode 100644 arch/x86/entry/entry_fred.c create mode 100644 arch/x86/include/asm/event-type.h create mode 100644 arch/x86/include/asm/fred.h create mode 100644 arch/x86/kernel/fred.c