On 03.07.2019 13:36, Jan Beulich wrote:
> The write-discard property of the type can't be represented in IOMMU
> page table entries. Make sure the respective checks / tracking can't
> race, by utilizing the domain lock. The other sides of the sharing/
> paging/log-dirty exclusion checks should subsequently perhaps also be
> put under that lock then.
>
> Take the opportunity and also convert neighboring bool_t to bool in
> struct hvm_domain.
>
> Signed-off-by: Jan Beulich <jbeul...@suse.com>
Alongside Paul's R-b could I get an ack or otherwise from you?
Thanks, Jan
> ---
> v2: Don't set p2m_ram_ro_used when failing the request.
>
> --- a/xen/arch/x86/hvm/dm.c
> +++ b/xen/arch/x86/hvm/dm.c
> @@ -255,16 +255,33 @@ static int set_mem_type(struct domain *d
>
> mem_type = array_index_nospec(data->mem_type, ARRAY_SIZE(memtype));
>
> - if ( mem_type == HVMMEM_ioreq_server )
> + switch ( mem_type )
> {
> unsigned int flags;
>
> + case HVMMEM_ioreq_server:
> if ( !hap_enabled(d) )
> return -EOPNOTSUPP;
>
> /* Do not change to HVMMEM_ioreq_server if no ioreq server mapped.
> */
> if ( !p2m_get_ioreq_server(d, &flags) )
> return -EINVAL;
> +
> + break;
> +
> + case HVMMEM_ram_ro:
> + /* p2m_ram_ro can't be represented in IOMMU mappings. */
> + domain_lock(d);
> + if ( has_iommu_pt(d) )
> + rc = -EXDEV;
> + else
> + d->arch.hvm.p2m_ram_ro_used = true;
> + domain_unlock(d);
> +
> + if ( rc )
> + return rc;
> +
> + break;
> }
>
> while ( iter < data->nr )
> --- a/xen/drivers/passthrough/pci.c
> +++ b/xen/drivers/passthrough/pci.c
> @@ -1448,17 +1448,36 @@ static int assign_device(struct domain *
> if ( !iommu_enabled || !hd->platform_ops )
> return 0;
>
> - /* Prevent device assign if mem paging or mem sharing have been
> - * enabled for this domain */
> - if ( unlikely(d->arch.hvm.mem_sharing_enabled ||
> - vm_event_check_ring(d->vm_event_paging) ||
> + domain_lock(d);
> +
> + /*
> + * Prevent device assignment if any of
> + * - mem paging
> + * - mem sharing
> + * - the p2m_ram_ro type
> + * - global log-dirty mode
> + * are in use by this domain.
> + */
> + if ( unlikely(vm_event_check_ring(d->vm_event_paging) ||
> +#ifdef CONFIG_HVM
> + (is_hvm_domain(d) &&
> + (d->arch.hvm.mem_sharing_enabled ||
> + d->arch.hvm.p2m_ram_ro_used)) ||
> +#endif
> p2m_get_hostp2m(d)->global_logdirty) )
> + {
> + domain_unlock(d);
> return -EXDEV;
> + }
>
> if ( !pcidevs_trylock() )
> + {
> + domain_unlock(d);
> return -ERESTART;
> + }
>
> rc = iommu_construct(d);
> + domain_unlock(d);
> if ( rc )
> {
> pcidevs_unlock();
> --- a/xen/include/asm-x86/hvm/domain.h
> +++ b/xen/include/asm-x86/hvm/domain.h
> @@ -156,10 +156,11 @@ struct hvm_domain {
>
> struct viridian_domain *viridian;
>
> - bool_t hap_enabled;
> - bool_t mem_sharing_enabled;
> - bool_t qemu_mapcache_invalidate;
> - bool_t is_s3_suspended;
> + bool hap_enabled;
> + bool mem_sharing_enabled;
> + bool p2m_ram_ro_used;
> + bool qemu_mapcache_invalidate;
> + bool is_s3_suspended;
>
> /*
> * TSC value that VCPUs use to calculate their tsc_offset value.
> _______________________________________________
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>
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