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    SubjectRe: [PATCH v3 16/23] kvm: arm64: Forward safe PSCI SMCs coming from host
    On Thu, Nov 26, 2020 at 03:54:14PM +0000, David Brazdil wrote:
    > Forward the following PSCI SMCs issued by host to EL3 as they do not
    > require the hypervisor's intervention. This assumes that EL3 correctly
    > implements the PSCI specification.
    >
    > Only function IDs implemented in Linux are included.
    >
    > Where both 32-bit and 64-bit variants exist, it is assumed that the host
    > will always use the 64-bit variant.
    >
    > * SMCs that only return information about the system
    > * PSCI_VERSION - PSCI version implemented by EL3
    > * PSCI_FEATURES - optional features supported by EL3
    > * AFFINITY_INFO - power state of core/cluster
    > * MIGRATE_INFO_TYPE - whether Trusted OS can be migrated
    > * MIGRATE_INFO_UP_CPU - resident core of Trusted OS
    > * operations which do not affect the hypervisor
    > * MIGRATE - migrate Trusted OS to a different core
    > * SET_SUSPEND_MODE - toggle OS-initiated mode
    > * system shutdown/reset
    > * SYSTEM_OFF
    > * SYSTEM_RESET
    > * SYSTEM_RESET2

    What about SYSTEM_SUSPEND ?

    Lorenzo

    > Signed-off-by: David Brazdil <dbrazdil@google.com>
    > ---
    > arch/arm64/kvm/hyp/nvhe/psci-relay.c | 43 +++++++++++++++++++++++++++-
    > 1 file changed, 42 insertions(+), 1 deletion(-)
    >
    > diff --git a/arch/arm64/kvm/hyp/nvhe/psci-relay.c b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
    > index e7091d89f0fc..7aa87ab7f5ce 100644
    > --- a/arch/arm64/kvm/hyp/nvhe/psci-relay.c
    > +++ b/arch/arm64/kvm/hyp/nvhe/psci-relay.c
    > @@ -57,14 +57,51 @@ static bool is_psci_call(u64 func_id)
    > }
    > }
    >
    > +static unsigned long psci_call(unsigned long fn, unsigned long arg0,
    > + unsigned long arg1, unsigned long arg2)
    > +{
    > + struct arm_smccc_res res;
    > +
    > + arm_smccc_1_1_smc(fn, arg0, arg1, arg2, &res);
    > + return res.a0;
    > +}
    > +
    > +static unsigned long psci_forward(struct kvm_cpu_context *host_ctxt)
    > +{
    > + return psci_call(cpu_reg(host_ctxt, 0), cpu_reg(host_ctxt, 1),
    > + cpu_reg(host_ctxt, 2), cpu_reg(host_ctxt, 3));
    > +}
    > +
    > +static __noreturn unsigned long psci_forward_noreturn(struct kvm_cpu_context *host_ctxt)
    > +{
    > + psci_forward(host_ctxt);
    > + hyp_panic(); /* unreachable */
    > +}
    > +
    > static unsigned long psci_0_1_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
    > {
    > - return PSCI_RET_NOT_SUPPORTED;
    > + if (func_id == kvm_host_psci_function_id[PSCI_FN_CPU_OFF])
    > + return psci_forward(host_ctxt);
    > + else if (func_id == kvm_host_psci_function_id[PSCI_FN_MIGRATE])
    > + return psci_forward(host_ctxt);
    > + else
    > + return PSCI_RET_NOT_SUPPORTED;
    > }
    >
    > static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
    > {
    > switch (func_id) {
    > + case PSCI_0_2_FN_PSCI_VERSION:
    > + case PSCI_0_2_FN_CPU_OFF:
    > + case PSCI_0_2_FN64_AFFINITY_INFO:
    > + case PSCI_0_2_FN64_MIGRATE:
    > + case PSCI_0_2_FN_MIGRATE_INFO_TYPE:
    > + case PSCI_0_2_FN64_MIGRATE_INFO_UP_CPU:
    > + return psci_forward(host_ctxt);
    > + case PSCI_0_2_FN_SYSTEM_OFF:
    > + case PSCI_0_2_FN_SYSTEM_RESET:
    > + psci_forward_noreturn(host_ctxt);
    > + unreachable();
    > default:
    > return PSCI_RET_NOT_SUPPORTED;
    > }
    > @@ -73,6 +110,10 @@ static unsigned long psci_0_2_handler(u64 func_id, struct kvm_cpu_context *host_
    > static unsigned long psci_1_0_handler(u64 func_id, struct kvm_cpu_context *host_ctxt)
    > {
    > switch (func_id) {
    > + case PSCI_1_0_FN_PSCI_FEATURES:
    > + case PSCI_1_0_FN_SET_SUSPEND_MODE:
    > + case PSCI_1_1_FN64_SYSTEM_RESET2:
    > + return psci_forward(host_ctxt);
    > default:
    > return psci_0_2_handler(func_id, host_ctxt);
    > }
    > --
    > 2.29.2.454.gaff20da3a2-goog
    >

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