On 03/01/17 13:26, David Gibson wrote:
> On Thu, Dec 22, 2016 at 12:13:12PM +1100, Alexey Kardashevskiy wrote:
>> KVM_CAP_SPAPR_TCE capability allows creating TCE tables in KVM which
>> allows having in-kernel acceleration for H_PUT_TCE_xxx hypercalls.
>> However it only supports 32bit DMA windows at zero bus offset.
>>
>> There is a new KVM_CAP_SPAPR_TCE_64 capability which supports 64bit
>> window size, variable page size and bus offset.
>>
>> This makes use of the new capability. The kernel headers are already
>> updated as the kernel support went in to v4.6.
>>
>> Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
>> ---
>> target-ppc/kvm_ppc.h | 12 +++++++-----
>> hw/ppc/spapr_iommu.c | 8 +++++---
>> target-ppc/kvm.c | 48 +++++++++++++++++++++++++++++++++++++-----------
>> 3 files changed, 49 insertions(+), 19 deletions(-)
>>
>> diff --git a/target-ppc/kvm_ppc.h b/target-ppc/kvm_ppc.h
>> index bd1d78bfbe..14320c2378 100644
>> --- a/target-ppc/kvm_ppc.h
>> +++ b/target-ppc/kvm_ppc.h
>> @@ -36,8 +36,9 @@ int kvmppc_booke_watchdog_enable(PowerPCCPU *cpu);
>> #ifndef CONFIG_USER_ONLY
>> off_t kvmppc_alloc_rma(void **rma);
>> bool kvmppc_spapr_use_multitce(void);
>> -void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int
>> *pfd,
>> - bool need_vfio);
>> +void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t page_shift,
>> + uint64_t bus_offset, uint32_t nb_table,
>> + int *pfd, bool need_vfio);
>> int kvmppc_remove_spapr_tce(void *table, int pfd, uint32_t window_size);
>> int kvmppc_reset_htab(int shift_hint);
>> uint64_t kvmppc_rma_size(uint64_t current_size, unsigned int hash_shift);
>> @@ -168,9 +169,10 @@ static inline bool kvmppc_spapr_use_multitce(void)
>> return false;
>> }
>>
>> -static inline void *kvmppc_create_spapr_tce(uint32_t liobn,
>> - uint32_t window_size, int *fd,
>> - bool need_vfio)
>> +static inline void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t
>> page_shift,
>> + uint64_t bus_offset,
>> + uint32_t nb_table,
>> + int *pfd, bool need_vfio)
>> {
>> return NULL;
>> }
>> diff --git a/hw/ppc/spapr_iommu.c b/hw/ppc/spapr_iommu.c
>> index ae30bbe30f..29c80bb3c8 100644
>> --- a/hw/ppc/spapr_iommu.c
>> +++ b/hw/ppc/spapr_iommu.c
>> @@ -79,15 +79,16 @@ static IOMMUAccessFlags
>> spapr_tce_iommu_access_flags(uint64_t tce)
>>
>> static uint64_t *spapr_tce_alloc_table(uint32_t liobn,
>> uint32_t page_shift,
>> + uint64_t bus_offset,
>> uint32_t nb_table,
>> int *fd,
>> bool need_vfio)
>> {
>> uint64_t *table = NULL;
>> - uint64_t window_size = (uint64_t)nb_table << page_shift;
>>
>> - if (kvm_enabled() && !(window_size >> 32)) {
>> - table = kvmppc_create_spapr_tce(liobn, window_size, fd, need_vfio);
>> + if (kvm_enabled()) {
>
> This is broken. Previously, if we had a >4GiB window, we'd fall back
> to managing it in userspace, which would work, albeit slowly. Now, if
> you have an older kernel which doesn't support KVM_CAP_SPAPR_TCE_64 it
> will attempt to allocate it in the kernel, and fail completely.
No, kvmppc_create_spapr_tce() would return NULL and right after that there
is a "if (!table)" (it can be seen at the end of this chunk) to handle the
failure.
>
>> + table = kvmppc_create_spapr_tce(liobn, page_shift, bus_offset,
>> nb_table,
>> + fd, need_vfio);
>> }
>>
>> if (!table) {
>> @@ -342,6 +343,7 @@ void spapr_tce_table_enable(sPAPRTCETable *tcet,
>> tcet->nb_table = nb_table;
>> tcet->table = spapr_tce_alloc_table(tcet->liobn,
>> tcet->page_shift,
>> + tcet->bus_offset,
>> tcet->nb_table,
>> &tcet->fd,
>> tcet->need_vfio);
>> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
>> index 9c4834c4fc..6e91a4d8bb 100644
>> --- a/target-ppc/kvm.c
>> +++ b/target-ppc/kvm.c
>> @@ -71,6 +71,7 @@ static int cap_booke_sregs;
>> static int cap_ppc_smt;
>> static int cap_ppc_rma;
>> static int cap_spapr_tce;
>> +static int cap_spapr_tce_64;
>> static int cap_spapr_multitce;
>> static int cap_spapr_vfio;
>> static int cap_hior;
>> @@ -123,6 +124,7 @@ int kvm_arch_init(MachineState *ms, KVMState *s)
>> cap_ppc_smt = kvm_check_extension(s, KVM_CAP_PPC_SMT);
>> cap_ppc_rma = kvm_check_extension(s, KVM_CAP_PPC_RMA);
>> cap_spapr_tce = kvm_check_extension(s, KVM_CAP_SPAPR_TCE);
>> + cap_spapr_tce_64 = kvm_check_extension(s, KVM_CAP_SPAPR_TCE_64);
>> cap_spapr_multitce = kvm_check_extension(s, KVM_CAP_SPAPR_MULTITCE);
>> cap_spapr_vfio = false;
>> cap_one_reg = kvm_check_extension(s, KVM_CAP_ONE_REG);
>> @@ -2201,13 +2203,10 @@ bool kvmppc_spapr_use_multitce(void)
>> return cap_spapr_multitce;
>> }
>>
>> -void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t window_size, int
>> *pfd,
>> - bool need_vfio)
>> +void *kvmppc_create_spapr_tce(uint32_t liobn, uint32_t page_shift,
>> + uint64_t bus_offset, uint32_t nb_table,
>> + int *pfd, bool need_vfio)
>> {
>> - struct kvm_create_spapr_tce args = {
>> - .liobn = liobn,
>> - .window_size = window_size,
>> - };
>> long len;
>> int fd;
>> void *table;
>> @@ -2220,14 +2219,41 @@ void *kvmppc_create_spapr_tce(uint32_t liobn,
>> uint32_t window_size, int *pfd,
>> return NULL;
>> }
>>
>> - fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_SPAPR_TCE, &args);
>> - if (fd < 0) {
>> - fprintf(stderr, "KVM: Failed to create TCE table for liobn 0x%x\n",
>> - liobn);
>> + if (cap_spapr_tce_64) {
>> + struct kvm_create_spapr_tce_64 args = {
>> + .liobn = liobn,
>> + .page_shift = page_shift,
>> + .offset = bus_offset >> page_shift,
>> + .size = nb_table,
>> + .flags = 0
>> + };
>> + fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_SPAPR_TCE_64, &args);
>> + if (fd < 0) {
>> + fprintf(stderr,
>> + "KVM: Failed to create TCE64 table for liobn 0x%x\n",
>> + liobn);
>> + return NULL;
>> + }
>> + } else if (cap_spapr_tce) {
>> + uint64_t window_size = (uint64_t) nb_table << page_shift;
>> + struct kvm_create_spapr_tce args = {
>> + .liobn = liobn,
>> + .window_size = window_size,
>> + };
>> + if ((window_size != args.window_size) || bus_offset) {
>> + return NULL;
>> + }
>> + fd = kvm_vm_ioctl(kvm_state, KVM_CREATE_SPAPR_TCE, &args);
>> + if (fd < 0) {
>> + fprintf(stderr, "KVM: Failed to create TCE table for liobn
>> 0x%x\n",
>> + liobn);
>> + return NULL;
>> + }
>> + } else {
>> return NULL;
>> }
>>
>> - len = (window_size / SPAPR_TCE_PAGE_SIZE) * sizeof(uint64_t);
>> + len = nb_table * sizeof(uint64_t);
>> /* FIXME: round this up to page size */
>>
>> table = mmap(NULL, len, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
>
--
Alexey
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