Add the documentation for new UAPI when guest consumes uncorrectable but recoverable memory error (UER). This new UAPI enables userspace to inject SEA into the guest. Tested: make htmldocs and proofreading Signed-off-by: Jiaqi Yan <jiaqiyan@xxxxxxxxxx> --- Documentation/virt/kvm/api.rst | 46 ++++++++++++++++++++++++++++------ 1 file changed, 39 insertions(+), 7 deletions(-) diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst index 454c2aaa155e5..67645bdb66fe5 100644 --- a/Documentation/virt/kvm/api.rst +++ b/Documentation/virt/kvm/api.rst @@ -1288,16 +1288,48 @@ ARM64: User space may need to inject several types of events to the guest. +Inject SError +~~~~~~~~~~~~~ + Set the pending SError exception state for this VCPU. It is not possible to 'cancel' an Serror that has been made pending. -If the guest performed an access to I/O memory which could not be handled by -userspace, for example because of missing instruction syndrome decode -information or because there is no device mapped at the accessed IPA, then -userspace can ask the kernel to inject an external abort using the address -from the exiting fault on the VCPU. It is a programming error to set -ext_dabt_pending after an exit which was not either KVM_EXIT_MMIO or -KVM_EXIT_ARM_NISV. This feature is only available if the system supports +Inject SEA +~~~~~~~~~~ + +- If the guest performed an access to I/O memory which could not be handled by + userspace, for example because of missing instruction syndrome decode + information or because there is no device mapped at the accessed IPA, then + userspace can ask the kernel to inject an external abort using the address + from the exiting fault on the VCPU. + +- If the guest consumed an uncorrectable memory error, and RAS extension in + Trusted Firmware choosed to notify PE with SEA, KVM and core kernel may have + to handle the memory poison consumption when host APEI was unable to claim + the SEA. For the following type of faults, KVM sends SIGBUS to current thread + (i.e. VMM in EL0) with si_code=BUS_OBJERR: + + - Synchronous External abort, not on translation table walk or hardware + update of translation table. + + - Synchronous External abort on translation table walk or hardware update of + translation table, level 1. + + - Synchronous parity or ECC error on memory access, not on translation table + walk. + + - Synchronous parity or ECC error on memory access on translation table walk + or hardware update of translation table, level 1. + + If the memory error's physical address is available, si_addr will be the + error's host virtual address in VM's memory space; otherwise si_addr is zero. + When userspace VMM is interrupted by such SIGBUS, it can ask KVM to replay + an external abort into guest. + +It is a programming error to set ext_dabt_pending after an exit which was not +KVM_EXIT_MMIO, not KVM_EXIT_ARM_NISV, and not interrupted by BUS_OBJERR SIGBUS. + +This feature is only available if the system supports KVM_CAP_ARM_INJECT_EXT_DABT. This is a helper which provides commonality in how userspace reports accesses for the above cases to guests, across different userspace implementations. Nevertheless, userspace can still emulate all Arm -- 2.47.0.338.g60cca15819-goog
