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author | Suresh Warrier <warrier@linux.vnet.ibm.com> | 2016-08-19 15:35:46 +1000 |
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committer | Paul Mackerras <paulus@ozlabs.org> | 2016-09-09 16:25:25 +1000 |
commit | 37f55d30df2eef89b97d627e5830beb6983c4101 (patch) | |
tree | 18142e71cb5a8cb8f1cf418c4f9028d46176c2e9 /arch/powerpc/kvm/book3s_hv_builtin.c | |
parent | 99212c864e1f6d2800e62bc8c52d6335bfca029f (diff) | |
download | linux-37f55d30df2eef89b97d627e5830beb6983c4101.tar.bz2 |
KVM: PPC: Book3S HV: Convert kvmppc_read_intr to a C function
Modify kvmppc_read_intr to make it a C function. Because it is called
from kvmppc_check_wake_reason, any of the assembler code that calls
either kvmppc_read_intr or kvmppc_check_wake_reason now has to assume
that the volatile registers might have been modified.
This also adds in the optimization of clearing saved_xirr in the case
where we completely handle and EOI an IPI. Without this, the next
device interrupt will require two trips through the host interrupt
handling code.
[paulus@ozlabs.org - made kvmppc_check_wake_reason create a stack frame
when it is calling kvmppc_read_intr, which means we can set r12 to
the trap number (0x500) after the call to kvmppc_read_intr, instead
of using r31. Also moved the deliver_guest_interrupt label so as to
restore XER and CTR, plus other minor tweaks.]
Signed-off-by: Suresh Warrier <warrier@linux.vnet.ibm.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch/powerpc/kvm/book3s_hv_builtin.c')
-rw-r--r-- | arch/powerpc/kvm/book3s_hv_builtin.c | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c index 5f0380db3eab..b476a6af893f 100644 --- a/arch/powerpc/kvm/book3s_hv_builtin.c +++ b/arch/powerpc/kvm/book3s_hv_builtin.c @@ -25,6 +25,7 @@ #include <asm/xics.h> #include <asm/dbell.h> #include <asm/cputhreads.h> +#include <asm/io.h> #define KVM_CMA_CHUNK_ORDER 18 @@ -286,3 +287,86 @@ void kvmhv_commence_exit(int trap) struct kvmppc_host_rm_ops *kvmppc_host_rm_ops_hv; EXPORT_SYMBOL_GPL(kvmppc_host_rm_ops_hv); + +/* + * Determine what sort of external interrupt is pending (if any). + * Returns: + * 0 if no interrupt is pending + * 1 if an interrupt is pending that needs to be handled by the host + * -1 if there was a guest wakeup IPI (which has now been cleared) + */ + +long kvmppc_read_intr(void) +{ + unsigned long xics_phys; + u32 h_xirr; + __be32 xirr; + u32 xisr; + u8 host_ipi; + + /* see if a host IPI is pending */ + host_ipi = local_paca->kvm_hstate.host_ipi; + if (host_ipi) + return 1; + + /* Now read the interrupt from the ICP */ + xics_phys = local_paca->kvm_hstate.xics_phys; + if (unlikely(!xics_phys)) + return 1; + + /* + * Save XIRR for later. Since we get control in reverse endian + * on LE systems, save it byte reversed and fetch it back in + * host endian. Note that xirr is the value read from the + * XIRR register, while h_xirr is the host endian version. + */ + xirr = _lwzcix(xics_phys + XICS_XIRR); + h_xirr = be32_to_cpu(xirr); + local_paca->kvm_hstate.saved_xirr = h_xirr; + xisr = h_xirr & 0xffffff; + /* + * Ensure that the store/load complete to guarantee all side + * effects of loading from XIRR has completed + */ + smp_mb(); + + /* if nothing pending in the ICP */ + if (!xisr) + return 0; + + /* We found something in the ICP... + * + * If it is an IPI, clear the MFRR and EOI it. + */ + if (xisr == XICS_IPI) { + _stbcix(xics_phys + XICS_MFRR, 0xff); + _stwcix(xics_phys + XICS_XIRR, xirr); + /* + * Need to ensure side effects of above stores + * complete before proceeding. + */ + smp_mb(); + + /* + * We need to re-check host IPI now in case it got set in the + * meantime. If it's clear, we bounce the interrupt to the + * guest + */ + host_ipi = local_paca->kvm_hstate.host_ipi; + if (unlikely(host_ipi != 0)) { + /* We raced with the host, + * we need to resend that IPI, bummer + */ + _stbcix(xics_phys + XICS_MFRR, IPI_PRIORITY); + /* Let side effects complete */ + smp_mb(); + return 1; + } + + /* OK, it's an IPI for us */ + local_paca->kvm_hstate.saved_xirr = 0; + return -1; + } + + return 1; +} |