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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] query the page type of a hvm page from within a hvm guest
On Mon, May 02, Jan Beulich wrote:
> >>> On 02.05.11 at 11:17, Olaf Hering <olaf@xxxxxxxxx> wrote:
> > On Thu, Apr 07, Tim Deegan wrote:
> >
> >> Hi,
> >>
> >> At 11:12 +0100 on 07 Apr (1302174722), Olaf Hering wrote:
> >> > If the crash kernel had a way to ask the hypervisor wether a specific
> >> > guest gfn is ballooned and thus backed by ram, the load issue would not
> >> > happen. There seems to be no interface to query the type of a guest gfn
> >> > from within the hvm guest.
> >> >
> >> > Any ideas how to implement that?
> >> > I see HVMOP_set_mem_type, but no HVMOP_get_mem_type.
> >>
> >> Feel free to add HVMOP_get_mem_type. I don't think any great harm can
> >> come from allowing the guest to query its own memory status.
> >
> > This version works for me, tested with xen 4.0.1 and SLES11 SP1 kernel.
> > The actual kernel interface needs to be send to lkml.
> >
> > Is there an u8 for padding required after mem_type in xen_hvm_get_mem_type?
> > Should HVMOP_get_mem_type just check for p2m_is_mmio() or return every
> > possible hvmmem_type_t value?
>
> I'd say the latter, even if you don't use it at present.
So what about this version then?
---
unmodified_drivers/linux-2.6/platform-pci/platform-pci.c | 36 +++++++++++++++
xen/arch/ia64/vmx/vmx_hypercall.c | 1
xen/arch/x86/hvm/hvm.c | 27 +++++++++++
xen/include/public/hvm/hvm_op.h | 25 ++++++++--
4 files changed, 84 insertions(+), 5 deletions(-)
diff -r 2f08c89b767d unmodified_drivers/linux-2.6/platform-pci/platform-pci.c
--- a/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c Wed Apr 20
17:13:08 2011 +0100
+++ b/unmodified_drivers/linux-2.6/platform-pci/platform-pci.c Mon May 02
17:42:57 2011 +0200
@@ -349,6 +349,32 @@ static int check_platform_magic(struct d
return -ENODEV;
}
+#ifdef HAVE_OLDMEM_PFN_IS_RAM
+static int xen_oldmem_pfn_is_ram(unsigned long pfn)
+{
+ struct xen_hvm_get_mem_type a;
+ int ret;
+
+ a.domid = DOMID_SELF;
+ a.pfn = pfn;
+ if (HYPERVISOR_hvm_op(HVMOP_get_mem_type, &a))
+ return -ENXIO;
+
+ switch (a.mem_type) {
+ case HVMMEM_mmio_dm:
+ ret = 0;
+ break;
+ case HVMMEM_ram_rw:
+ case HVMMEM_ram_ro:
+ default:
+ ret = 1;
+ break;
+ }
+
+ return ret;
+}
+#endif
+
static int __devinit platform_pci_init(struct pci_dev *pdev,
const struct pci_device_id *ent)
{
@@ -417,6 +443,9 @@ static int __devinit platform_pci_init(s
if ((ret = xen_panic_handler_init()))
goto out;
+#ifdef HAVE_OLDMEM_PFN_IS_RAM
+ register_oldmem_pfn_is_ram(&xen_oldmem_pfn_is_ram);
+#endif
out:
if (ret) {
pci_release_region(pdev, 0);
diff -r 2f08c89b767d xen/arch/ia64/vmx/vmx_hypercall.c
--- a/xen/arch/ia64/vmx/vmx_hypercall.c Wed Apr 20 17:13:08 2011 +0100
+++ b/xen/arch/ia64/vmx/vmx_hypercall.c Mon May 02 17:42:57 2011 +0200
@@ -217,6 +217,7 @@ do_hvm_op(unsigned long op, XEN_GUEST_HA
break;
}
+ case HVMOP_get_mem_type:
case HVMOP_set_mem_type:
case HVMOP_set_mem_access:
case HVMOP_get_mem_access:
diff -r 2f08c89b767d xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c Wed Apr 20 17:13:08 2011 +0100
+++ b/xen/arch/x86/hvm/hvm.c Mon May 02 17:42:57 2011 +0200
@@ -3676,6 +3676,37 @@ long do_hvm_op(unsigned long op, XEN_GUE
break;
}
+ case HVMOP_get_mem_type:
+ {
+ struct xen_hvm_get_mem_type a;
+ struct domain *d;
+ p2m_type_t t;
+
+ if ( copy_from_guest(&a, arg, 1) )
+ return -EFAULT;
+
+ rc = rcu_lock_remote_target_domain_by_id(a.domid, &d);
+ if ( rc != 0 )
+ return rc;
+
+ rc = -EINVAL;
+ if ( is_hvm_domain(d) )
+ {
+ gfn_to_mfn_unshare(p2m_get_hostp2m(d), a.pfn, &t, 0);
+ if ( p2m_is_mmio(t) )
+ a.mem_type = HVMMEM_mmio_dm;
+ else if ( p2m_is_readonly(t) )
+ a.mem_type = HVMMEM_ram_ro;
+ else if ( p2m_is_ram(t) )
+ a.mem_type = HVMMEM_ram_rw;
+ else
+ a.mem_type = HVMMEM_mmio_dm;
+ rc = copy_to_guest(arg, &a, 1) ? -EFAULT : 0;
+ }
+ rcu_unlock_domain(d);
+ break;
+ }
+
case HVMOP_set_mem_type:
{
struct xen_hvm_set_mem_type a;
diff -r 2f08c89b767d xen/include/public/hvm/hvm_op.h
--- a/xen/include/public/hvm/hvm_op.h Wed Apr 20 17:13:08 2011 +0100
+++ b/xen/include/public/hvm/hvm_op.h Mon May 02 17:42:57 2011 +0200
@@ -76,6 +76,12 @@ DEFINE_XEN_GUEST_HANDLE(xen_hvm_set_pci_
/* Flushes all VCPU TLBs: @arg must be NULL. */
#define HVMOP_flush_tlbs 5
+typedef enum {
+ HVMMEM_ram_rw, /* Normal read/write guest RAM */
+ HVMMEM_ram_ro, /* Read-only; writes are discarded */
+ HVMMEM_mmio_dm, /* Reads and write go to the device model */
+} hvmmem_type_t;
+
/* Following tools-only interfaces may change in future. */
#if defined(__XEN__) || defined(__XEN_TOOLS__)
@@ -109,11 +115,6 @@ typedef struct xen_hvm_modified_memory x
DEFINE_XEN_GUEST_HANDLE(xen_hvm_modified_memory_t);
#define HVMOP_set_mem_type 8
-typedef enum {
- HVMMEM_ram_rw, /* Normal read/write guest RAM */
- HVMMEM_ram_ro, /* Read-only; writes are discarded */
- HVMMEM_mmio_dm, /* Reads and write go to the device model */
-} hvmmem_type_t;
/* Notify that a region of memory is to be treated in a specific way. */
struct xen_hvm_set_mem_type {
/* Domain to be updated. */
@@ -223,6 +224,20 @@ struct xen_hvm_inject_trap {
typedef struct xen_hvm_inject_trap xen_hvm_inject_trap_t;
DEFINE_XEN_GUEST_HANDLE(xen_hvm_inject_trap_t);
+#define HVMOP_get_mem_type 15
+/* Return hvmmem_type_t for the specified pfn. */
+struct xen_hvm_get_mem_type {
+ /* Domain to be queried. */
+ domid_t domid;
+ /* OUT variable. */
+ uint8_t mem_type;
+ /* IN variable. */
+ uint64_t pfn;
+};
+typedef struct xen_hvm_get_mem_type xen_hvm_get_mem_type_t;
+DEFINE_XEN_GUEST_HANDLE(xen_hvm_get_mem_type_t);
+
+
#endif /* defined(__XEN__) || defined(__XEN_TOOLS__) */
#endif /* __XEN_PUBLIC_HVM_HVM_OP_H__ */
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