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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v3 4/6] ioreq-server: on-demand creation of ioreq server
On Wed, Mar 5, 2014 at 2:47 PM, Paul Durrant <paul.durrant@xxxxxxxxxx> wrote:
> This patch only creates the ioreq server when the legacy HVM parameters
> are touched by an emulator. It also lays some groundwork for supporting
> multiple IOREQ servers. For instance, it introduces ioreq server reference
> counting which is not strictly necessary at this stage but will become so
> when ioreq servers can be destroyed prior the domain dying.
>
> There is a significant change in the layout of the special pages reserved
> in xc_hvm_build_x86.c. This is so that we can 'grow' them downwards without
> moving pages such as the xenstore page when building a domain that can
> support more than one emulator.
>
> Signed-off-by: Paul Durrant <paul.durrant@xxxxxxxxxx>
> ---
> tools/libxc/xc_hvm_build_x86.c | 40 +++++--
> xen/arch/x86/hvm/hvm.c | 240
> +++++++++++++++++++++++++---------------
> 2 files changed, 176 insertions(+), 104 deletions(-)
>
> diff --git a/tools/libxc/xc_hvm_build_x86.c b/tools/libxc/xc_hvm_build_x86.c
> index dd3b522..b65e702 100644
> --- a/tools/libxc/xc_hvm_build_x86.c
> +++ b/tools/libxc/xc_hvm_build_x86.c
> @@ -41,13 +41,12 @@
> #define SPECIALPAGE_PAGING 0
> #define SPECIALPAGE_ACCESS 1
> #define SPECIALPAGE_SHARING 2
> -#define SPECIALPAGE_BUFIOREQ 3
> -#define SPECIALPAGE_XENSTORE 4
> -#define SPECIALPAGE_IOREQ 5
> -#define SPECIALPAGE_IDENT_PT 6
> -#define SPECIALPAGE_CONSOLE 7
> -#define NR_SPECIAL_PAGES 8
> -#define special_pfn(x) (0xff000u - NR_SPECIAL_PAGES + (x))
> +#define SPECIALPAGE_XENSTORE 3
> +#define SPECIALPAGE_IDENT_PT 4
> +#define SPECIALPAGE_CONSOLE 5
> +#define SPECIALPAGE_IOREQ 6
> +#define NR_SPECIAL_PAGES SPECIALPAGE_IOREQ + 2 /* ioreq server needs 2
> pages */
> +#define special_pfn(x) (0xff000u - 1 - (x))
>
> #define VGA_HOLE_SIZE (0x20)
>
> @@ -114,7 +113,7 @@ static void build_hvm_info(void *hvm_info_page, uint64_t
> mem_size,
> /* Memory parameters. */
> hvm_info->low_mem_pgend = lowmem_end >> PAGE_SHIFT;
> hvm_info->high_mem_pgend = highmem_end >> PAGE_SHIFT;
> - hvm_info->reserved_mem_pgstart = special_pfn(0);
> + hvm_info->reserved_mem_pgstart = special_pfn(0) - NR_SPECIAL_PAGES;
It might be better to #define this up above, just below special_pfn()?
If we do that, and make the change below, then the "direction of
growth" will be encoded all in one place.
>
> /* Finish with the checksum. */
> for ( i = 0, sum = 0; i < hvm_info->length; i++ )
> @@ -473,6 +472,23 @@ static int setup_guest(xc_interface *xch,
> munmap(hvm_info_page, PAGE_SIZE);
>
> /* Allocate and clear special pages. */
> +
> + DPRINTF("%d SPECIAL PAGES:\n", NR_SPECIAL_PAGES);
> + DPRINTF(" PAGING: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_PAGING));
> + DPRINTF(" ACCESS: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_ACCESS));
> + DPRINTF(" SHARING: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_SHARING));
> + DPRINTF(" STORE: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_XENSTORE));
> + DPRINTF(" IDENT_PT: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_IDENT_PT));
> + DPRINTF(" CONSOLE: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_CONSOLE));
> + DPRINTF(" IOREQ: %"PRI_xen_pfn"\n",
> + (xen_pfn_t)special_pfn(SPECIALPAGE_IOREQ));
> +
> for ( i = 0; i < NR_SPECIAL_PAGES; i++ )
> {
> xen_pfn_t pfn = special_pfn(i);
> @@ -488,10 +504,6 @@ static int setup_guest(xc_interface *xch,
>
> xc_set_hvm_param(xch, dom, HVM_PARAM_STORE_PFN,
> special_pfn(SPECIALPAGE_XENSTORE));
> - xc_set_hvm_param(xch, dom, HVM_PARAM_BUFIOREQ_PFN,
> - special_pfn(SPECIALPAGE_BUFIOREQ));
> - xc_set_hvm_param(xch, dom, HVM_PARAM_IOREQ_PFN,
> - special_pfn(SPECIALPAGE_IOREQ));
> xc_set_hvm_param(xch, dom, HVM_PARAM_CONSOLE_PFN,
> special_pfn(SPECIALPAGE_CONSOLE));
> xc_set_hvm_param(xch, dom, HVM_PARAM_PAGING_RING_PFN,
> @@ -500,6 +512,10 @@ static int setup_guest(xc_interface *xch,
> special_pfn(SPECIALPAGE_ACCESS));
> xc_set_hvm_param(xch, dom, HVM_PARAM_SHARING_RING_PFN,
> special_pfn(SPECIALPAGE_SHARING));
> + xc_set_hvm_param(xch, dom, HVM_PARAM_IOREQ_PFN,
> + special_pfn(SPECIALPAGE_IOREQ));
> + xc_set_hvm_param(xch, dom, HVM_PARAM_BUFIOREQ_PFN,
> + special_pfn(SPECIALPAGE_IOREQ) - 1);
If we say "special_pfn(SPECIALPAGE_IOREQ+1)", it doesn't assume that
things grow a specific direction.
>
> /*
> * Identity-map page table is required for running with CR0.PG=0 when
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index bbf9577..22b2a2c 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -366,22 +366,9 @@ bool_t hvm_io_pending(struct vcpu *v)
> return ( p->state != STATE_IOREQ_NONE );
> }
>
> -void hvm_do_resume(struct vcpu *v)
> +static void hvm_wait_on_io(struct domain *d, ioreq_t *p)
> {
> - struct domain *d = v->domain;
> - struct hvm_ioreq_server *s = d->arch.hvm_domain.ioreq_server;
> - ioreq_t *p;
> -
> - check_wakeup_from_wait();
> -
> - if ( is_hvm_vcpu(v) )
> - pt_restore_timer(v);
> -
> - if ( !s )
> - goto check_inject_trap;
> -
> /* NB. Optimised for common case (p->state == STATE_IOREQ_NONE). */
> - p = get_ioreq(s, v->vcpu_id);
> while ( p->state != STATE_IOREQ_NONE )
> {
> switch ( p->state )
> @@ -397,12 +384,29 @@ void hvm_do_resume(struct vcpu *v)
> break;
> default:
> gdprintk(XENLOG_ERR, "Weird HVM iorequest state %d.\n",
> p->state);
> - domain_crash(v->domain);
> + domain_crash(d);
> return; /* bail */
> }
> }
> +}
> +
> +void hvm_do_resume(struct vcpu *v)
> +{
> + struct domain *d = v->domain;
> + struct hvm_ioreq_server *s = d->arch.hvm_domain.ioreq_server;
> +
> + check_wakeup_from_wait();
> +
> + if ( is_hvm_vcpu(v) )
> + pt_restore_timer(v);
> +
> + if ( s )
> + {
> + ioreq_t *p = get_ioreq(s, v->vcpu_id);
> +
> + hvm_wait_on_io(d, p);
> + }
>
> - check_inject_trap:
> /* Inject pending hw/sw trap */
> if ( v->arch.hvm_vcpu.inject_trap.vector != -1 )
> {
> @@ -411,11 +415,13 @@ void hvm_do_resume(struct vcpu *v)
> }
> }
>
> -static void hvm_init_ioreq_page(
> - struct domain *d, struct hvm_ioreq_page *iorp)
> +static void hvm_init_ioreq_page(struct hvm_ioreq_server *s, bool_t buf)
> {
> + struct hvm_ioreq_page *iorp;
> +
> + iorp = buf ? &s->buf_ioreq : &s->ioreq;
> +
> spin_lock_init(&iorp->lock);
> - domain_pause(d);
> }
>
> void destroy_ring_for_helper(
> @@ -431,16 +437,13 @@ void destroy_ring_for_helper(
> }
> }
>
> -static void hvm_destroy_ioreq_page(
> - struct domain *d, struct hvm_ioreq_page *iorp)
> +static void hvm_destroy_ioreq_page(struct hvm_ioreq_server *s, bool_t buf)
> {
> - spin_lock(&iorp->lock);
> + struct hvm_ioreq_page *iorp;
>
> - ASSERT(d->is_dying);
> + iorp = buf ? &s->buf_ioreq : &s->ioreq;
>
> destroy_ring_for_helper(&iorp->va, iorp->page);
> -
> - spin_unlock(&iorp->lock);
BTW, is there a reason you're getting rid of the locks here?
-George
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