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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] Xen/hypercall: Update vcpu_op to take an unsigned vcpuid
On Fri, 16 Jan 2015, Andrew Cooper wrote:
> This has no guest-visible change, but makes the Hypervisor side bounds
> checking more simple.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> CC: Keir Fraser <keir@xxxxxxx>
> CC: Jan Beulich <JBeulich@xxxxxxxx>
> CC: Ian Campbell <ian.campbell@xxxxxxxxxx>
> CC: Stefano Stabellini <stefano.stabellini@xxxxxxxxxx>
> CC: Tim Deegan <tim@xxxxxxx>
>
For the tiny arm part:
Acked-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>
> There are no functional changes as a result of this patch, but I have an RFC
> improvement to suggest.
>
> The bounds check against MAX_VIRT_CPUS is spurious now that PVH domains can
> use vcpu_op hypercalls. It is fine as MAX_VIRT_CPUS (8K) is far higher than
> current 128 limit for HVM guests, but there is nothing conceptually preventing
> an HVM domain from having more than 8k CPUs (x2apic allows for 2^32 unique
> ids).
>
> I propose dropping the MAX_VIRT_CPU bounds check completely, and relying on
> d->max_vcpus to be within the approprate bounds. This will result in a guest
> visible change insofar that some of their -EINVAL errors will turn into
> -ENOENT, which is why this is suggestion is RFC.
> ---
> xen/arch/arm/domain.c | 2 +-
> xen/arch/x86/hvm/hvm.c | 4 ++--
> xen/common/compat/domain.c | 6 +++---
> xen/common/domain.c | 6 +++---
> xen/include/asm-arm/hypercall.h | 2 +-
> xen/include/public/vcpu.h | 2 +-
> xen/include/xen/hypercall.h | 4 ++--
> 7 files changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 7221bc8..cfc7ab4 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -777,7 +777,7 @@ void arch_dump_domain_info(struct domain *d)
> }
>
>
> -long do_arm_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> +long do_arm_vcpu_op(int cmd, unsigned int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> {
> switch ( cmd )
> {
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 8b06bfd..e096094 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4659,7 +4659,7 @@ static long hvm_physdev_op(int cmd,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> }
>
> static long hvm_vcpu_op(
> - int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> + int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> {
> long rc;
>
> @@ -4718,7 +4718,7 @@ static long hvm_memory_op_compat32(int cmd,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> }
>
> static long hvm_vcpu_op_compat32(
> - int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> + int cmd, unsigned vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> {
> long rc;
>
> diff --git a/xen/common/compat/domain.c b/xen/common/compat/domain.c
> index b4be3b3..510843d 100644
> --- a/xen/common/compat/domain.c
> +++ b/xen/common/compat/domain.c
> @@ -23,13 +23,13 @@ CHECK_SIZE_(struct, vcpu_info);
> CHECK_vcpu_register_vcpu_info;
> #undef xen_vcpu_register_vcpu_info
>
> -int compat_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> +int compat_vcpu_op(int cmd, unsigned int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> {
> struct domain *d = current->domain;
> struct vcpu *v;
> int rc = 0;
>
> - if ( (vcpuid < 0) || (vcpuid >= MAX_VIRT_CPUS) )
> + if ( vcpuid >= MAX_VIRT_CPUS )
> return -EINVAL;
>
> if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) == NULL )
> @@ -59,7 +59,7 @@ int compat_vcpu_op(int cmd, int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> domain_unlock(d);
>
> if ( rc == -ERESTART )
> - rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iih",
> + rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iuh",
> cmd, vcpuid, arg);
>
> xfree(cmp_ctxt);
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index 336e9ea..e02823e 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -1139,14 +1139,14 @@ void unmap_vcpu_info(struct vcpu *v)
> put_page_and_type(mfn_to_page(mfn));
> }
>
> -long do_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg)
> +long do_vcpu_op(int cmd, unsigned int vcpuid, XEN_GUEST_HANDLE_PARAM(void)
> arg)
> {
> struct domain *d = current->domain;
> struct vcpu *v;
> struct vcpu_guest_context *ctxt;
> long rc = 0;
>
> - if ( (vcpuid < 0) || (vcpuid >= MAX_VIRT_CPUS) )
> + if ( vcpuid >= MAX_VIRT_CPUS )
> return -EINVAL;
>
> if ( vcpuid >= d->max_vcpus || (v = d->vcpu[vcpuid]) == NULL )
> @@ -1174,7 +1174,7 @@ long do_vcpu_op(int cmd, int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg)
> free_vcpu_guest_context(ctxt);
>
> if ( rc == -ERESTART )
> - rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iih",
> + rc = hypercall_create_continuation(__HYPERVISOR_vcpu_op, "iuh",
> cmd, vcpuid, arg);
>
> break;
> diff --git a/xen/include/asm-arm/hypercall.h b/xen/include/asm-arm/hypercall.h
> index 94a92d4..a0c5a31 100644
> --- a/xen/include/asm-arm/hypercall.h
> +++ b/xen/include/asm-arm/hypercall.h
> @@ -4,7 +4,7 @@
> #include <public/domctl.h> /* for arch_do_domctl */
> int do_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void) arg);
>
> -long do_arm_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE_PARAM(void) arg);
> +long do_arm_vcpu_op(int cmd, unsigned int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg);
>
> long subarch_do_domctl(struct xen_domctl *domctl, struct domain *d,
> XEN_GUEST_HANDLE_PARAM(xen_domctl_t) u_domctl);
> diff --git a/xen/include/public/vcpu.h b/xen/include/public/vcpu.h
> index e888daf..898b89f 100644
> --- a/xen/include/public/vcpu.h
> +++ b/xen/include/public/vcpu.h
> @@ -31,7 +31,7 @@
>
> /*
> * Prototype for this hypercall is:
> - * int vcpu_op(int cmd, int vcpuid, void *extra_args)
> + * long vcpu_op(int cmd, unsigned int vcpuid, void *extra_args)
> * @cmd == VCPUOP_??? (VCPU operation).
> * @vcpuid == VCPU to operate on.
> * @extra_args == Operation-specific extra arguments (NULL if none).
> diff --git a/xen/include/xen/hypercall.h b/xen/include/xen/hypercall.h
> index 8c55779..eda8a36 100644
> --- a/xen/include/xen/hypercall.h
> +++ b/xen/include/xen/hypercall.h
> @@ -109,7 +109,7 @@ do_vm_assist(
> extern long
> do_vcpu_op(
> int cmd,
> - int vcpuid,
> + unsigned int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg);
>
> struct vcpu;
> @@ -160,7 +160,7 @@ compat_grant_table_op(
> extern int
> compat_vcpu_op(
> int cmd,
> - int vcpuid,
> + unsigned int vcpuid,
> XEN_GUEST_HANDLE_PARAM(void) arg);
>
> extern int
> --
> 1.7.10.4
>
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