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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v6 10/15] x86/altp2m: add remaining support routines.
On 07/21/2015 12:58 AM, Ed White wrote:
> Add the remaining routines required to support enabling the alternate
> p2m functionality.
>
> Signed-off-by: Ed White <edmund.h.white@xxxxxxxxx>
>
> Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> ---
> xen/arch/x86/hvm/hvm.c | 58 +++++-
> xen/arch/x86/mm/hap/Makefile | 1 +
> xen/arch/x86/mm/hap/altp2m_hap.c | 98 ++++++++++
> xen/arch/x86/mm/p2m-ept.c | 3 +
> xen/arch/x86/mm/p2m.c | 385
> +++++++++++++++++++++++++++++++++++++++
> xen/include/asm-x86/hvm/altp2m.h | 4 +
> xen/include/asm-x86/p2m.h | 33 ++++
> 7 files changed, 576 insertions(+), 6 deletions(-)
> create mode 100644 xen/arch/x86/mm/hap/altp2m_hap.c
>
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index f0ab4d4..38cf0c6 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -2856,10 +2856,11 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> mfn_t mfn;
> struct vcpu *curr = current;
> struct domain *currd = curr->domain;
> - struct p2m_domain *p2m;
> + struct p2m_domain *p2m, *hostp2m;
> int rc, fall_through = 0, paged = 0;
> int sharing_enomem = 0;
> vm_event_request_t *req_ptr = NULL;
> + bool_t ap2m_active = 0;
>
> /* On Nested Virtualization, walk the guest page table.
> * If this succeeds, all is fine.
> @@ -2919,11 +2920,31 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> goto out;
> }
>
> - p2m = p2m_get_hostp2m(currd);
> - mfn = get_gfn_type_access(p2m, gfn, &p2mt, &p2ma,
> + ap2m_active = altp2m_active(currd);
> +
> + /* Take a lock on the host p2m speculatively, to avoid potential
> + * locking order problems later and to handle unshare etc.
> + */
> + hostp2m = p2m_get_hostp2m(currd);
> + mfn = get_gfn_type_access(hostp2m, gfn, &p2mt, &p2ma,
> P2M_ALLOC | (npfec.write_access ? P2M_UNSHARE
> : 0),
> NULL);
>
> + if ( ap2m_active )
> + {
> + if ( altp2m_hap_nested_page_fault(curr, gpa, gla, npfec, &p2m) == 1 )
> + {
> + /* entry was lazily copied from host -- retry */
> + __put_gfn(hostp2m, gfn);
> + rc = 1;
> + goto out;
> + }
> +
> + mfn = get_gfn_type_access(p2m, gfn, &p2mt, &p2ma, 0, NULL);
> + }
> + else
> + p2m = hostp2m;
> +
> /* Check access permissions first, then handle faults */
> if ( mfn_x(mfn) != INVALID_MFN )
> {
> @@ -2963,6 +2984,20 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
>
> if ( violation )
> {
> + /* Should #VE be emulated for this fault? */
> + if ( p2m_is_altp2m(p2m) && !cpu_has_vmx_virt_exceptions )
> + {
> + bool_t sve;
> +
> + p2m->get_entry(p2m, gfn, &p2mt, &p2ma, 0, NULL, &sve);
> +
> + if ( !sve && altp2m_vcpu_emulate_ve(curr) )
> + {
> + rc = 1;
> + goto out_put_gfn;
> + }
> + }
> +
> if ( p2m_mem_access_check(gpa, gla, npfec, &req_ptr) )
> {
> fall_through = 1;
> @@ -2982,7 +3017,9 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> (npfec.write_access &&
> (p2m_is_discard_write(p2mt) || (p2mt == p2m_mmio_write_dm))) )
> {
> - put_gfn(currd, gfn);
> + __put_gfn(p2m, gfn);
> + if ( ap2m_active )
> + __put_gfn(hostp2m, gfn);
>
> rc = 0;
> if ( unlikely(is_pvh_domain(currd)) )
> @@ -3011,6 +3048,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> /* Spurious fault? PoD and log-dirty also take this path. */
> if ( p2m_is_ram(p2mt) )
> {
> + rc = 1;
> /*
> * Page log dirty is always done with order 0. If this mfn resides in
> * a large page, we do not change other pages type within that large
> @@ -3019,9 +3057,15 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> if ( npfec.write_access )
> {
> paging_mark_dirty(currd, mfn_x(mfn));
> + /* If p2m is really an altp2m, unlock here to avoid lock ordering
> + * violation when the change below is propagated from host p2m */
> + if ( ap2m_active )
> + __put_gfn(p2m, gfn);
> p2m_change_type_one(currd, gfn, p2m_ram_logdirty, p2m_ram_rw);
> + __put_gfn(ap2m_active ? hostp2m : p2m, gfn);
> +
> + goto out;
> }
> - rc = 1;
> goto out_put_gfn;
> }
>
> @@ -3031,7 +3075,9 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> rc = fall_through;
>
> out_put_gfn:
> - put_gfn(currd, gfn);
> + __put_gfn(p2m, gfn);
> + if ( ap2m_active )
> + __put_gfn(hostp2m, gfn);
> out:
> /* All of these are delayed until we exit, since we might
> * sleep on event ring wait queues, and we must not hold
> diff --git a/xen/arch/x86/mm/hap/Makefile b/xen/arch/x86/mm/hap/Makefile
> index 68f2bb5..216cd90 100644
> --- a/xen/arch/x86/mm/hap/Makefile
> +++ b/xen/arch/x86/mm/hap/Makefile
> @@ -4,6 +4,7 @@ obj-y += guest_walk_3level.o
> obj-$(x86_64) += guest_walk_4level.o
> obj-y += nested_hap.o
> obj-y += nested_ept.o
> +obj-y += altp2m_hap.o
>
> guest_walk_%level.o: guest_walk.c Makefile
> $(CC) $(CFLAGS) -DGUEST_PAGING_LEVELS=$* -c $< -o $@
> diff --git a/xen/arch/x86/mm/hap/altp2m_hap.c
> b/xen/arch/x86/mm/hap/altp2m_hap.c
> new file mode 100644
> index 0000000..52c7877
> --- /dev/null
> +++ b/xen/arch/x86/mm/hap/altp2m_hap.c
> @@ -0,0 +1,98 @@
> +/******************************************************************************
> + * arch/x86/mm/hap/altp2m_hap.c
> + *
> + * Copyright (c) 2014 Intel Corporation.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> + */
> +
> +#include <asm/domain.h>
> +#include <asm/page.h>
> +#include <asm/paging.h>
> +#include <asm/p2m.h>
> +#include <asm/hap.h>
> +#include <asm/hvm/altp2m.h>
> +
> +#include "private.h"
> +
> +/*
> + * If the fault is for a not present entry:
> + * if the entry in the host p2m has a valid mfn, copy it and retry
> + * else indicate that outer handler should handle fault
> + *
> + * If the fault is for a present entry:
> + * indicate that outer handler should handle fault
> + */
> +
> +int
> +altp2m_hap_nested_page_fault(struct vcpu *v, paddr_t gpa,
> + unsigned long gla, struct npfec npfec,
> + struct p2m_domain **ap2m)
> +{
> + struct p2m_domain *hp2m = p2m_get_hostp2m(v->domain);
> + p2m_type_t p2mt;
> + p2m_access_t p2ma;
> + unsigned int page_order;
> + gfn_t gfn = _gfn(paddr_to_pfn(gpa));
> + unsigned long mask;
> + mfn_t mfn;
> + int rv;
> +
> + *ap2m = p2m_get_altp2m(v);
> +
> + mfn = get_gfn_type_access(*ap2m, gfn_x(gfn), &p2mt, &p2ma,
> + 0, &page_order);
> + __put_gfn(*ap2m, gfn_x(gfn));
> +
> + if ( mfn_x(mfn) != INVALID_MFN )
> + return 0;
> +
> + mfn = get_gfn_type_access(hp2m, gfn_x(gfn), &p2mt, &p2ma,
> + P2M_ALLOC | P2M_UNSHARE, &page_order);
> + put_gfn(hp2m->domain, gfn_x(gfn));
To quote myself:
---
Please do at least give this function a name that reflects what it
does (i.e., try to propagate changes from the host p2m to the altp2m),
and change this put_gfn() to match the __put_gfn() above.
I'd prefer it if you moved this into mm/p2m.c as well.
---
-George
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