| Message ID | 20170407173307.9788-16-andre.przywara@arm.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Andre, On 04/07/2017 06:32 PM, Andre Przywara wrote: > This function allows to copy a chunk of data from and to guest physical > memory. It looks up the associated page from the guest's p2m tree > and maps this page temporarily for the time of the access. > This function was originally written by Vijaya as part of an earlier series: > https://patchwork.kernel.org/patch/8177251i This likely means the From: should be "Vijaya...". > > Signed-off-by: Vijaya Kumar K <Vijaya.Kumar@caviumnetworks.com> > Signed-off-by: Andre Przywara <andre.przywara@arm.com> > --- > xen/arch/arm/vgic.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++ > xen/include/asm-arm/vgic.h | 3 +++ > 2 files changed, 50 insertions(+) > > diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c > index e6c97b2..5c68fe7 100644 > --- a/xen/arch/arm/vgic.c > +++ b/xen/arch/arm/vgic.c > @@ -20,6 +20,7 @@ > #include <xen/bitops.h> > #include <xen/lib.h> > #include <xen/init.h> > +#include <xen/domain_page.h> > #include <xen/softirq.h> > #include <xen/irq.h> > #include <xen/sched.h> > @@ -598,6 +599,52 @@ void vgic_free_virq(struct domain *d, unsigned int virq) > } > > /* > + * Temporarily map one physical guest page and copy data to or from it. > + * The data to be copied cannot cross a page boundary. > + */ > +int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf, > + uint32_t size, bool_t is_write) > +{ > + struct page_info *page; > + uint64_t offset; > + p2m_type_t p2mt; > + void *p; > + > + page = get_page_from_gfn(d, paddr_to_pfn(gpa), &p2mt, P2M_ALLOC); > + if ( !page ) > + { > + printk(XENLOG_G_ERR "d%d: vITS: Failed to get table entry\n", > + d->domain_id); > + return -EINVAL; > + } > + > + if ( !p2m_is_ram(p2mt) ) > + { > + put_page(page); > + printk(XENLOG_G_ERR "d%d: vITS: memory used by the ITS should be RAM.", > + d->domain_id); > + return -EINVAL; > + } > + > + p = __map_domain_page(page); > + /* Offset within the mapped page */ > + offset = gpa & ~PAGE_MASK; > + /* Do not cross a page boundary. */ > + if ( size > (PAGE_SIZE - offset) ) > + size = PAGE_SIZE - offset; Hmmmm.... it is not what I meant by a check. If a user uses this function he will expect *all* the buffer filled and not only a part if a page boundary is crossed. This would be a potential security issue if the buffer is then written back to the guest memory (I know this is not the case today, but still...). I think it would be better if we return -EINVAL if the in this case. > + > + if ( is_write ) > + memcpy(p + offset, buf, size); > + else > + memcpy(buf, p + offset, size); > + > + unmap_domain_page(p); > + put_page(page); > + > + return 0; > +} > + > +/* > * Local variables: > * mode: C > * c-file-style: "BSD" > diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h > index 52856ca..967c2be 100644 > --- a/xen/include/asm-arm/vgic.h > +++ b/xen/include/asm-arm/vgic.h > @@ -319,6 +319,9 @@ extern void register_vgic_ops(struct domain *d, const struct vgic_ops *ops); > int vgic_v2_init(struct domain *d, int *mmio_count); > int vgic_v3_init(struct domain *d, int *mmio_count); > > +int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf, > + uint32_t size, bool_t is_write); > + > extern int domain_vgic_register(struct domain *d, int *mmio_count); > extern int vcpu_vgic_free(struct vcpu *v); > extern bool vgic_to_sgi(struct vcpu *v, register_t sgir, > Cheers,
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c index e6c97b2..5c68fe7 100644 --- a/xen/arch/arm/vgic.c +++ b/xen/arch/arm/vgic.c @@ -20,6 +20,7 @@ #include <xen/bitops.h> #include <xen/lib.h> #include <xen/init.h> +#include <xen/domain_page.h> #include <xen/softirq.h> #include <xen/irq.h> #include <xen/sched.h> @@ -598,6 +599,52 @@ void vgic_free_virq(struct domain *d, unsigned int virq) } /* + * Temporarily map one physical guest page and copy data to or from it. + * The data to be copied cannot cross a page boundary. + */ +int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf, + uint32_t size, bool_t is_write) +{ + struct page_info *page; + uint64_t offset; + p2m_type_t p2mt; + void *p; + + page = get_page_from_gfn(d, paddr_to_pfn(gpa), &p2mt, P2M_ALLOC); + if ( !page ) + { + printk(XENLOG_G_ERR "d%d: vITS: Failed to get table entry\n", + d->domain_id); + return -EINVAL; + } + + if ( !p2m_is_ram(p2mt) ) + { + put_page(page); + printk(XENLOG_G_ERR "d%d: vITS: memory used by the ITS should be RAM.", + d->domain_id); + return -EINVAL; + } + + p = __map_domain_page(page); + /* Offset within the mapped page */ + offset = gpa & ~PAGE_MASK; + /* Do not cross a page boundary. */ + if ( size > (PAGE_SIZE - offset) ) + size = PAGE_SIZE - offset; + + if ( is_write ) + memcpy(p + offset, buf, size); + else + memcpy(buf, p + offset, size); + + unmap_domain_page(p); + put_page(page); + + return 0; +} + +/* * Local variables: * mode: C * c-file-style: "BSD" diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h index 52856ca..967c2be 100644 --- a/xen/include/asm-arm/vgic.h +++ b/xen/include/asm-arm/vgic.h @@ -319,6 +319,9 @@ extern void register_vgic_ops(struct domain *d, const struct vgic_ops *ops); int vgic_v2_init(struct domain *d, int *mmio_count); int vgic_v3_init(struct domain *d, int *mmio_count); +int vgic_access_guest_memory(struct domain *d, paddr_t gpa, void *buf, + uint32_t size, bool_t is_write); + extern int domain_vgic_register(struct domain *d, int *mmio_count); extern int vcpu_vgic_free(struct vcpu *v); extern bool vgic_to_sgi(struct vcpu *v, register_t sgir,