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    Subject[PATCH AUTOSEL 5.10 02/15] KVM: arm64: Save PSTATE early on exit
    Date
    From: Marc Zyngier <maz@kernel.org>

    [ Upstream commit 83bb2c1a01d7127d5adc7d69d7aaa3f7072de2b4 ]

    In order to be able to use primitives such as vcpu_mode_is_32bit(),
    we need to synchronize the guest PSTATE. However, this is currently
    done deep into the bowels of the world-switch code, and we do have
    helpers evaluating this much earlier (__vgic_v3_perform_cpuif_access
    and handle_aarch32_guest, for example).

    Move the saving of the guest pstate into the early fixups, which
    cures the first issue. The second one will be addressed separately.

    Tested-by: Fuad Tabba <tabba@google.com>
    Reviewed-by: Fuad Tabba <tabba@google.com>
    Signed-off-by: Marc Zyngier <maz@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    arch/arm64/kvm/hyp/include/hyp/switch.h | 6 ++++++
    arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h | 7 ++++++-
    2 files changed, 12 insertions(+), 1 deletion(-)

    diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
    index 1f875a8f20c47..8116ae1e636a2 100644
    --- a/arch/arm64/kvm/hyp/include/hyp/switch.h
    +++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
    @@ -406,6 +406,12 @@ static inline bool __hyp_handle_ptrauth(struct kvm_vcpu *vcpu)
    */
    static inline bool fixup_guest_exit(struct kvm_vcpu *vcpu, u64 *exit_code)
    {
    + /*
    + * Save PSTATE early so that we can evaluate the vcpu mode
    + * early on.
    + */
    + vcpu->arch.ctxt.regs.pstate = read_sysreg_el2(SYS_SPSR);
    +
    if (ARM_EXCEPTION_CODE(*exit_code) != ARM_EXCEPTION_IRQ)
    vcpu->arch.fault.esr_el2 = read_sysreg_el2(SYS_ESR);

    diff --git a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
    index cce43bfe158fa..0eacfb9d17b02 100644
    --- a/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
    +++ b/arch/arm64/kvm/hyp/include/hyp/sysreg-sr.h
    @@ -54,7 +54,12 @@ static inline void __sysreg_save_el1_state(struct kvm_cpu_context *ctxt)
    static inline void __sysreg_save_el2_return_state(struct kvm_cpu_context *ctxt)
    {
    ctxt->regs.pc = read_sysreg_el2(SYS_ELR);
    - ctxt->regs.pstate = read_sysreg_el2(SYS_SPSR);
    + /*
    + * Guest PSTATE gets saved at guest fixup time in all
    + * cases. We still need to handle the nVHE host side here.
    + */
    + if (!has_vhe() && ctxt->__hyp_running_vcpu)
    + ctxt->regs.pstate = read_sysreg_el2(SYS_SPSR);

    if (cpus_have_final_cap(ARM64_HAS_RAS_EXTN))
    ctxt_sys_reg(ctxt, DISR_EL1) = read_sysreg_s(SYS_VDISR_EL2);
    --
    2.33.0
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