KVM: PPC: Book3S HV: Remove unused nested HV tests in XICS emulation

Commit f3c18e9342a44 ("KVM: PPC: Book3S HV: Use XICS hypercalls when
running as a nested hypervisor") added nested HV tests in XICS
hypercalls, but not all are required.

* icp_eoi is only called by kvmppc_deliver_irq_passthru which is only
  called by kvmppc_check_passthru which is only caled by
  kvmppc_read_one_intr.

* kvmppc_read_one_intr is only called by kvmppc_read_intr which is only
  called by the L0 HV rmhandlers code.

* kvmhv_rm_send_ipi is called by:
  - kvmhv_interrupt_vcore which is only called by kvmhv_commence_exit
    which is only called by the L0 HV rmhandlers code.
  - icp_send_hcore_msg which is only called by icp_rm_set_vcpu_irq.
  - icp_rm_set_vcpu_irq which is only called by icp_rm_try_update
  - icp_rm_set_vcpu_irq is not nested HV safe because it writes to
    LPCR directly without a kvmhv_on_pseries test. Nested handlers
    should not in general be using the rm handlers.

The important test seems to be in kvmppc_ipi_thread, which sends the
virt-mode H_IPI handler kick to use smp_call_function rather than
msgsnd.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210528090752.3542186-26-npiggin@gmail.com

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index 8d669a0..259492b 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -199,15 +199,6 @@ void kvmhv_rm_send_ipi(int cpu)
        void __iomem *xics_phys;
        unsigned long msg = PPC_DBELL_TYPE(PPC_DBELL_SERVER);
 
-       /* For a nested hypervisor, use the XICS via hcall */
-       if (kvmhv_on_pseries()) {
-               unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-
-               plpar_hcall_raw(H_IPI, retbuf, get_hard_smp_processor_id(cpu),
-                               IPI_PRIORITY);
-               return;
-       }
-
        /* On POWER9 we can use msgsnd for any destination cpu. */
        if (cpu_has_feature(CPU_FTR_ARCH_300)) {
                msg |= get_hard_smp_processor_id(cpu);
@@ -420,19 +411,12 @@ static long kvmppc_read_one_intr(bool *again)
                return 1;
 
        /* Now read the interrupt from the ICP */
-       if (kvmhv_on_pseries()) {
-               unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-
-               rc = plpar_hcall_raw(H_XIRR, retbuf, 0xFF);
-               xirr = cpu_to_be32(retbuf[0]);
-       } else {
-               xics_phys = local_paca->kvm_hstate.xics_phys;
-               rc = 0;
-               if (!xics_phys)
-                       rc = opal_int_get_xirr(&xirr, false);
-               else
-                       xirr = __raw_rm_readl(xics_phys + XICS_XIRR);
-       }
+       xics_phys = local_paca->kvm_hstate.xics_phys;
+       rc = 0;
+       if (!xics_phys)
+               rc = opal_int_get_xirr(&xirr, false);
+       else
+               xirr = __raw_rm_readl(xics_phys + XICS_XIRR);
        if (rc < 0)
                return 1;
 
@@ -461,13 +445,7 @@ static long kvmppc_read_one_intr(bool *again)
         */
        if (xisr == XICS_IPI) {
                rc = 0;
-               if (kvmhv_on_pseries()) {
-                       unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-
-                       plpar_hcall_raw(H_IPI, retbuf,
-                                       hard_smp_processor_id(), 0xff);
-                       plpar_hcall_raw(H_EOI, retbuf, h_xirr);
-               } else if (xics_phys) {
+               if (xics_phys) {
                        __raw_rm_writeb(0xff, xics_phys + XICS_MFRR);
                        __raw_rm_writel(xirr, xics_phys + XICS_XIRR);
                } else {
@@ -493,13 +471,7 @@ static long kvmppc_read_one_intr(bool *again)
                        /* We raced with the host,
                         * we need to resend that IPI, bummer
                         */
-                       if (kvmhv_on_pseries()) {
-                               unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-
-                               plpar_hcall_raw(H_IPI, retbuf,
-                                               hard_smp_processor_id(),
-                                               IPI_PRIORITY);
-                       } else if (xics_phys)
+                       if (xics_phys)
                                __raw_rm_writeb(IPI_PRIORITY,
                                                xics_phys + XICS_MFRR);
                        else

diff --git a/arch/powerpc/kvm/book3s_hv_rm_xics.c b/arch/powerpc/kvm/book3s_hv_rm_xics.c
index c2c9c73..0a11ec8 100644 (file)
--- a/arch/powerpc/kvm/book3s_hv_rm_xics.c
+++ b/arch/powerpc/kvm/book3s_hv_rm_xics.c
@@ -141,13 +141,6 @@ static void icp_rm_set_vcpu_irq(struct kvm_vcpu *vcpu,
                return;
        }
 
-       if (xive_enabled() && kvmhv_on_pseries()) {
-               /* No XICS access or hypercalls available, too hard */
-               this_icp->rm_action |= XICS_RM_KICK_VCPU;
-               this_icp->rm_kick_target = vcpu;
-               return;
-       }
-
        /*
         * Check if the core is loaded,
         * if not, find an available host core to post to wake the VCPU,
@@ -771,14 +764,6 @@ static void icp_eoi(struct irq_chip *c, u32 hwirq, __be32 xirr, bool *again)
        void __iomem *xics_phys;
        int64_t rc;
 
-       if (kvmhv_on_pseries()) {
-               unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
-
-               iosync();
-               plpar_hcall_raw(H_EOI, retbuf, hwirq);
-               return;
-       }
-
        rc = pnv_opal_pci_msi_eoi(c, hwirq);
 
        if (rc)