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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] mem_access: Use monitor_traps instead of mem_access_send_req
On 07/28/2016 10:35 PM, Tamas K Lengyel wrote:
> The two functions monitor_traps and mem_access_send_req duplicate
> some of the same functionality. The mem_access_send_req however leaves a
> lot of the standard vm_event fields to be filled by other functions.
>
> Since mem_access events go on the monitor ring in this patch we consolidate
> all paths to use monitor_traps to place events on the ring and to fill in
> the common parts of the requests.
>
> Signed-off-by: Tamas K Lengyel <tamas.lengyel@xxxxxxxxxxxx>
> ---
> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
> Cc: Julien Grall <julien.grall@xxxxxxx>
> Cc: Jan Beulich <jbeulich@xxxxxxxx>
> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
> Cc: Razvan Cojocaru <rcojocaru@xxxxxxxxxxxxxxx>
> Cc: George Dunlap <george.dunlap@xxxxxxxxxxxxx>
> ---
> xen/arch/arm/p2m.c | 69
> +++++++++++++++++++--------------------
> xen/arch/x86/hvm/hvm.c | 16 ++++++---
> xen/arch/x86/hvm/monitor.c | 6 ++++
> xen/arch/x86/mm/p2m.c | 24 ++------------
> xen/common/mem_access.c | 11 -------
> xen/include/asm-x86/hvm/monitor.h | 2 ++
> xen/include/asm-x86/p2m.h | 13 +++++---
> xen/include/xen/mem_access.h | 7 ----
> 8 files changed, 63 insertions(+), 85 deletions(-)
>
> diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
> index d82349c..df898a3 100644
> --- a/xen/arch/arm/p2m.c
> +++ b/xen/arch/arm/p2m.c
> @@ -5,7 +5,7 @@
> #include <xen/domain_page.h>
> #include <xen/bitops.h>
> #include <xen/vm_event.h>
> -#include <xen/mem_access.h>
> +#include <xen/monitor.h>
> #include <xen/iocap.h>
> #include <public/vm_event.h>
> #include <asm/flushtlb.h>
> @@ -1642,12 +1642,41 @@ void __init setup_virt_paging(void)
> smp_call_function(setup_virt_paging_one, (void *)val, 1);
> }
>
> +static int
> +__p2m_mem_access_send_req(paddr_t gpa, vaddr_t gla, const struct npfec npfec,
> + xenmem_access_t xma)
> +{
> + struct vcpu *v = current;
> + vm_event_request_t req = {};
> + bool_t sync = (xma == XENMEM_access_n2rwx) ? 0 : 1;
> +
> + req.reason = VM_EVENT_REASON_MEM_ACCESS;
> +
> + /* Send request to mem access subscriber */
> + req.u.mem_access.gfn = gpa >> PAGE_SHIFT;
> + req.u.mem_access.offset = gpa & ((1 << PAGE_SHIFT) - 1);
> + if ( npfec.gla_valid )
> + {
> + req.u.mem_access.flags |= MEM_ACCESS_GLA_VALID;
> + req.u.mem_access.gla = gla;
> +
> + if ( npfec.kind == npfec_kind_with_gla )
> + req.u.mem_access.flags |= MEM_ACCESS_FAULT_WITH_GLA;
> + else if ( npfec.kind == npfec_kind_in_gpt )
> + req.u.mem_access.flags |= MEM_ACCESS_FAULT_IN_GPT;
> + }
> + req.u.mem_access.flags |= npfec.read_access ? MEM_ACCESS_R : 0;
> + req.u.mem_access.flags |= npfec.write_access ? MEM_ACCESS_W : 0;
> + req.u.mem_access.flags |= npfec.insn_fetch ? MEM_ACCESS_X : 0;
> +
> + return monitor_traps(v, sync, &req);
> +}
> +
> bool_t p2m_mem_access_check(paddr_t gpa, vaddr_t gla, const struct npfec
> npfec)
> {
> int rc;
> bool_t violation;
> xenmem_access_t xma;
> - vm_event_request_t *req;
> struct vcpu *v = current;
> struct p2m_domain *p2m = p2m_get_hostp2m(v->domain);
>
> @@ -1734,40 +1763,8 @@ bool_t p2m_mem_access_check(paddr_t gpa, vaddr_t gla,
> const struct npfec npfec)
> return false;
> }
>
> - req = xzalloc(vm_event_request_t);
> - if ( req )
> - {
> - req->reason = VM_EVENT_REASON_MEM_ACCESS;
> -
> - /* Pause the current VCPU */
> - if ( xma != XENMEM_access_n2rwx )
> - req->flags |= VM_EVENT_FLAG_VCPU_PAUSED;
> -
> - /* Send request to mem access subscriber */
> - req->u.mem_access.gfn = gpa >> PAGE_SHIFT;
> - req->u.mem_access.offset = gpa & ((1 << PAGE_SHIFT) - 1);
> - if ( npfec.gla_valid )
> - {
> - req->u.mem_access.flags |= MEM_ACCESS_GLA_VALID;
> - req->u.mem_access.gla = gla;
> -
> - if ( npfec.kind == npfec_kind_with_gla )
> - req->u.mem_access.flags |= MEM_ACCESS_FAULT_WITH_GLA;
> - else if ( npfec.kind == npfec_kind_in_gpt )
> - req->u.mem_access.flags |= MEM_ACCESS_FAULT_IN_GPT;
> - }
> - req->u.mem_access.flags |= npfec.read_access ? MEM_ACCESS_R : 0;
> - req->u.mem_access.flags |= npfec.write_access ? MEM_ACCESS_W : 0;
> - req->u.mem_access.flags |= npfec.insn_fetch ? MEM_ACCESS_X : 0;
> - req->vcpu_id = v->vcpu_id;
The line setting req->vcpu_id has been removed here ...
> -
> - mem_access_send_req(v->domain, req);
> - xfree(req);
> - }
> -
> - /* Pause the current VCPU */
> - if ( xma != XENMEM_access_n2rwx )
> - vm_event_vcpu_pause(v);
> + if ( __p2m_mem_access_send_req(gpa, gla, npfec, xma) < 0 )
> + domain_crash(v->domain);
>
> return false;
> }
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index daaee1d..688370d 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -1707,7 +1707,7 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> int rc, fall_through = 0, paged = 0;
> int sharing_enomem = 0;
> vm_event_request_t *req_ptr = NULL;
> - bool_t ap2m_active;
> + bool_t ap2m_active, sync = 0;
>
> /* On Nested Virtualization, walk the guest page table.
> * If this succeeds, all is fine.
> @@ -1846,11 +1846,12 @@ int hvm_hap_nested_page_fault(paddr_t gpa, unsigned
> long gla,
> }
> }
>
> - if ( p2m_mem_access_check(gpa, gla, npfec, &req_ptr) )
> - {
> + sync = p2m_mem_access_check(gpa, gla, npfec, &req_ptr);
> +
> + if ( !sync ) {
> fall_through = 1;
> } else {
> - /* Rights not promoted, vcpu paused, work here is done */
> + /* Rights not promoted (aka. sync event), work here is done
> */
> rc = 1;
> goto out_put_gfn;
> }
> @@ -1956,7 +1957,12 @@ out:
> }
> if ( req_ptr )
> {
> - mem_access_send_req(currd, req_ptr);
> + if ( hvm_monitor_mem_access(curr, sync, req_ptr) < 0 )
> + {
> + /* Crash the domain */
> + rc = 0;
> + }
> +
> xfree(req_ptr);
> }
> return rc;
> diff --git a/xen/arch/x86/hvm/monitor.c b/xen/arch/x86/hvm/monitor.c
> index 7277c12..c7285c6 100644
> --- a/xen/arch/x86/hvm/monitor.c
> +++ b/xen/arch/x86/hvm/monitor.c
> @@ -152,6 +152,12 @@ int hvm_monitor_cpuid(unsigned long insn_length)
> return monitor_traps(curr, 1, &req);
> }
>
> +int hvm_monitor_mem_access(struct vcpu* v, bool_t sync,
> + vm_event_request_t *req)
> +{
> + return monitor_traps(v, sync, req);
> +}
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index 812dbf6..27f9d26 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -1728,13 +1728,8 @@ bool_t p2m_mem_access_check(paddr_t gpa, unsigned long
> gla,
> if ( req )
> {
> *req_ptr = req;
> - req->reason = VM_EVENT_REASON_MEM_ACCESS;
> -
> - /* Pause the current VCPU */
> - if ( p2ma != p2m_access_n2rwx )
> - req->flags |= VM_EVENT_FLAG_VCPU_PAUSED;
>
> - /* Send request to mem event */
> + req->reason = VM_EVENT_REASON_MEM_ACCESS;
> req->u.mem_access.gfn = gfn;
> req->u.mem_access.offset = gpa & ((1 << PAGE_SHIFT) - 1);
> if ( npfec.gla_valid )
> @@ -1750,23 +1745,10 @@ bool_t p2m_mem_access_check(paddr_t gpa, unsigned
> long gla,
> req->u.mem_access.flags |= npfec.read_access ? MEM_ACCESS_R : 0;
> req->u.mem_access.flags |= npfec.write_access ? MEM_ACCESS_W : 0;
> req->u.mem_access.flags |= npfec.insn_fetch ? MEM_ACCESS_X : 0;
> - req->vcpu_id = v->vcpu_id;
... and here, and as such it doesn't seem to get set anywhere else now.
Am I missing an code path outside of this patch where req->vcpu_id is
being correctly set so this has become unnecessary?
Thanks,
Razvan
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