| Message ID | 20220224051439.640768-1-kaleshsingh@google.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: arm64: Hypervisor stack enhancements | expand |
On Wed, Feb 23, 2022 at 9:15 PM Kalesh Singh <kaleshsingh@google.com> wrote: > > Hi all, > > This is v3 of the nVHE hypervisor stack enhancements. Please find the latest version v4, posted at: https://lore.kernel.org/r/20220225033548.1912117-1-kaleshsingh@google.com/ Thanks, Kalesh > > Previous versions can be found at: > v2: https://lore.kernel.org/r/20220222165212.2005066-1-kaleshsingh@google.com/ > v1: https://lore.kernel.org/r/20220210224220.4076151-1-kaleshsingh@google.com/ > > The main update in this version is that the unwinder now uses the core logic > from the regular kernel stack unwinder to avoid duplicate code, per Mark; along > with fixes for the other issues identified in v2. > > The previous cover letter (with updated call trace) has been copied below. > > Thanks, > Kalesh > > ----- > > This series is based on 5.17-rc5 and adds the following stack features to > the KVM nVHE hypervisor: > > == Hyp Stack Guard Pages == > > Based on the technique used by arm64 VMAP_STACK to detect overflow. > i.e. the stack is aligned to twice its size which ensure that the > 'stack shift' bit of any valid SP is 0. The 'stack shift' bit can be > tested in the exception entry to detect overflow without corrupting GPRs. > > == Hyp Stack Unwinder == > > Based on the arm64 kernel stack unwinder > (See: arch/arm64/kernel/stacktrace.c) > > The unwinding and dumping of the hyp stack is not enabled by default and > depends on CONFIG_NVHE_EL2_DEBUG to avoid potential information leaks. > > When CONFIG_NVHE_EL2_DEBUG is enabled the host stage 2 protection is > disabled, allowing the host to read the hypervisor stack pages and unwind > the stack from EL1. This allows us to print the hypervisor stacktrace > before panicking the host; as shown below. > > Example call trace: > > [ 98.916444][ T426] kvm [426]: nVHE hyp panic at: [<ffffffc0096156fc>] __kvm_nvhe_overflow_stack+0x8/0x34! > [ 98.918360][ T426] nVHE HYP call trace: > [ 98.918692][ T426] kvm [426]: [<ffffffc009615aac>] __kvm_nvhe_cpu_prepare_nvhe_panic_info+0x4c/0x68 > [ 98.919545][ T426] kvm [426]: [<ffffffc0096159a4>] __kvm_nvhe_hyp_panic+0x2c/0xe8 > [ 98.920107][ T426] kvm [426]: [<ffffffc009615ad8>] __kvm_nvhe_hyp_panic_bad_stack+0x10/0x10 > [ 98.920665][ T426] kvm [426]: [<ffffffc009610a4c>] __kvm_nvhe___kvm_hyp_host_vector+0x24c/0x794 > [ 98.921292][ T426] kvm [426]: [<ffffffc009615718>] __kvm_nvhe_overflow_stack+0x24/0x34 > . . . > > [ 98.973382][ T426] kvm [426]: [<ffffffc009615718>] __kvm_nvhe_overflow_stack+0x24/0x34 > [ 98.973816][ T426] kvm [426]: [<ffffffc0096152f4>] __kvm_nvhe___kvm_vcpu_run+0x38/0x438 > [ 98.974255][ T426] kvm [426]: [<ffffffc009616f80>] __kvm_nvhe_handle___kvm_vcpu_run+0x1c4/0x364 > [ 98.974719][ T426] kvm [426]: [<ffffffc009616928>] __kvm_nvhe_handle_trap+0xa8/0x130 > [ 98.975152][ T426] kvm [426]: [<ffffffc009610064>] __kvm_nvhe___host_exit+0x64/0x64 > [ 98.975588][ T426] ---- end of nVHE HYP call trace ---- > > > Kalesh Singh (8): > KVM: arm64: Introduce hyp_alloc_private_va_range() > KVM: arm64: Introduce pkvm_alloc_private_va_range() > KVM: arm64: Add guard pages for KVM nVHE hypervisor stack > KVM: arm64: Add guard pages for pKVM (protected nVHE) hypervisor stack > KVM: arm64: Detect and handle hypervisor stack overflows > KVM: arm64: Add hypervisor overflow stack > KVM: arm64: Unwind and dump nVHE HYP stacktrace > KVM: arm64: Symbolize the nVHE HYP backtrace > > arch/arm64/include/asm/kvm_asm.h | 20 +++ > arch/arm64/include/asm/kvm_mmu.h | 4 + > arch/arm64/include/asm/stacktrace.h | 12 ++ > arch/arm64/kernel/stacktrace.c | 210 ++++++++++++++++++++++++--- > arch/arm64/kvm/Kconfig | 5 +- > arch/arm64/kvm/arm.c | 34 ++++- > arch/arm64/kvm/handle_exit.c | 16 +- > arch/arm64/kvm/hyp/include/nvhe/mm.h | 3 +- > arch/arm64/kvm/hyp/nvhe/host.S | 29 ++++ > arch/arm64/kvm/hyp/nvhe/hyp-main.c | 5 +- > arch/arm64/kvm/hyp/nvhe/mm.c | 51 ++++--- > arch/arm64/kvm/hyp/nvhe/setup.c | 25 +++- > arch/arm64/kvm/hyp/nvhe/switch.c | 30 +++- > arch/arm64/kvm/mmu.c | 62 +++++--- > scripts/kallsyms.c | 2 +- > 15 files changed, 422 insertions(+), 86 deletions(-) > > > base-commit: cfb92440ee71adcc2105b0890bb01ac3cddb8507 > -- > 2.35.1.473.g83b2b277ed-goog >