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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 2/4] libxc: support of linear p2m list for migration of pv-domains
In order to be able to migrate pv-domains with more than 512 GB of RAM
the p2m information can be specified by the guest kernel via a virtual
mapped linear p2m list instead of a 3 level tree.
Add support for this new p2m format in libxc.
As the sanity checking of the virtual p2m address needs defines for the
xen regions use those defines when doing page table checks as well.
There were two harmless off by one errors in normalise_pagetable()
being fixed by using those defines (xen_last set to 512 instead of
511), the other one is fixed directly.
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
Changes in V4:
- use correct format specifier for printing 64 bit values
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
tools/libxc/xc_sr_common_x86_pv.h | 7 ++
tools/libxc/xc_sr_save_x86_pv.c | 194 +++++++++++++++++++++++++++++++++++---
2 files changed, 188 insertions(+), 13 deletions(-)
diff --git a/tools/libxc/xc_sr_common_x86_pv.h
b/tools/libxc/xc_sr_common_x86_pv.h
index 3234944..f80c753 100644
--- a/tools/libxc/xc_sr_common_x86_pv.h
+++ b/tools/libxc/xc_sr_common_x86_pv.h
@@ -3,6 +3,13 @@
#include "xc_sr_common_x86.h"
+/* Virtual address ranges reserved for hypervisor. */
+#define HYPERVISOR_VIRT_START_X86_64 0xFFFF800000000000ULL
+#define HYPERVISOR_VIRT_END_X86_64 0xFFFF87FFFFFFFFFFULL
+
+#define HYPERVISOR_VIRT_START_X86_32 0x00000000F5800000ULL
+#define HYPERVISOR_VIRT_END_X86_32 0x00000000FFFFFFFFULL
+
/*
* Convert an mfn to a pfn, given Xen's m2p table.
*
diff --git a/tools/libxc/xc_sr_save_x86_pv.c b/tools/libxc/xc_sr_save_x86_pv.c
index d7acd37..5448f32 100644
--- a/tools/libxc/xc_sr_save_x86_pv.c
+++ b/tools/libxc/xc_sr_save_x86_pv.c
@@ -3,6 +3,12 @@
#include "xc_sr_common_x86_pv.h"
+/* Check a 64 bit virtual address for being canonical. */
+static inline bool is_canonical_address(xen_vaddr_t vaddr)
+{
+ return ((int64_t)vaddr >> 47) == ((int64_t)vaddr >> 63);
+}
+
/*
* Maps the guests shared info page.
*/
@@ -116,7 +122,7 @@ static int map_p2m_leaves(struct xc_sr_context *ctx,
xen_pfn_t *mfns,
* frames making up the guests p2m table. Construct a list of pfns making up
* the table.
*/
-static int map_p2m(struct xc_sr_context *ctx)
+static int map_p2m_tree(struct xc_sr_context *ctx)
{
/* Terminology:
*
@@ -138,8 +144,6 @@ static int map_p2m(struct xc_sr_context *ctx)
void *guest_fl = NULL;
size_t local_fl_size;
- ctx->x86_pv.max_pfn = GET_FIELD(ctx->x86_pv.shinfo, arch.max_pfn,
- ctx->x86_pv.width) - 1;
fpp = PAGE_SIZE / ctx->x86_pv.width;
fll_entries = (ctx->x86_pv.max_pfn / (fpp * fpp)) + 1;
if ( fll_entries > fpp )
@@ -270,6 +274,170 @@ err:
}
/*
+ * Map the guest p2m frames specified via a cr3 value, a virtual address, and
+ * the maximum pfn. PTE entries are 64 bits for both, 32 and 64 bit guests as
+ * in 32 bit case we support PAE guests only.
+ */
+static int map_p2m_list(struct xc_sr_context *ctx, uint64_t p2m_cr3)
+{
+ xc_interface *xch = ctx->xch;
+ xen_vaddr_t p2m_vaddr, p2m_end, mask, off;
+ xen_pfn_t p2m_mfn, mfn, saved_mfn, max_pfn;
+ uint64_t *ptes;
+ xen_pfn_t *mfns;
+ unsigned fpp, n_pages, level, shift, idx_start, idx_end, idx, saved_idx;
+ int rc = -1;
+
+ p2m_mfn = cr3_to_mfn(ctx, p2m_cr3);
+ assert(p2m_mfn != 0);
+ if ( p2m_mfn > ctx->x86_pv.max_mfn )
+ {
+ ERROR("Bad p2m_cr3 value %#" PRIx64, p2m_cr3);
+ errno = ERANGE;
+ return -1;
+ }
+
+ p2m_vaddr = GET_FIELD(ctx->x86_pv.shinfo, arch.p2m_vaddr,
+ ctx->x86_pv.width);
+ fpp = PAGE_SIZE / ctx->x86_pv.width;
+ ctx->x86_pv.p2m_frames = ctx->x86_pv.max_pfn / fpp + 1;
+ p2m_end = p2m_vaddr + ctx->x86_pv.p2m_frames * PAGE_SIZE - 1;
+
+ if ( ctx->x86_pv.width == 8 )
+ {
+ mask = 0x0000ffffffffffffULL;
+ if ( !is_canonical_address(p2m_vaddr) ||
+ !is_canonical_address(p2m_end) ||
+ p2m_end < p2m_vaddr ||
+ (p2m_vaddr <= HYPERVISOR_VIRT_END_X86_64 &&
+ p2m_end > HYPERVISOR_VIRT_START_X86_64) )
+ {
+ ERROR("Bad virtual p2m address range %#" PRIx64 "-%#" PRIx64,
+ p2m_vaddr, p2m_end);
+ errno = ERANGE;
+ return -1;
+ }
+ }
+ else
+ {
+ mask = 0x00000000ffffffffULL;
+ if ( p2m_vaddr > mask || p2m_end > mask || p2m_end < p2m_vaddr ||
+ (p2m_vaddr <= HYPERVISOR_VIRT_END_X86_32 &&
+ p2m_end > HYPERVISOR_VIRT_START_X86_32) )
+ {
+ ERROR("Bad virtual p2m address range %#" PRIx64 "-%#" PRIx64,
+ p2m_vaddr, p2m_end);
+ errno = ERANGE;
+ return -1;
+ }
+ }
+
+ DPRINTF("p2m list from %#" PRIx64 " to %#" PRIx64 ", root at %#lx",
+ p2m_vaddr, p2m_end, p2m_mfn);
+ DPRINTF("max_pfn %#lx, p2m_frames %d", ctx->x86_pv.max_pfn,
+ ctx->x86_pv.p2m_frames);
+
+ mfns = malloc(sizeof(*mfns));
+ if ( !mfns )
+ {
+ ERROR("Cannot allocate memory for array of %u mfns", 1);
+ goto err;
+ }
+ mfns[0] = p2m_mfn;
+ off = 0;
+ saved_mfn = 0;
+ idx_start = idx_end = saved_idx = 0;
+
+ for ( level = ctx->x86_pv.levels; level > 0; level-- )
+ {
+ n_pages = idx_end - idx_start + 1;
+ ptes = xc_map_foreign_pages(xch, ctx->domid, PROT_READ, mfns, n_pages);
+ if ( !ptes )
+ {
+ PERROR("Failed to map %u page table pages for p2m list", n_pages);
+ goto err;
+ }
+ free(mfns);
+
+ shift = level * 9 + 3;
+ idx_start = ((p2m_vaddr - off) & mask) >> shift;
+ idx_end = ((p2m_end - off) & mask) >> shift;
+ idx = idx_end - idx_start + 1;
+ mfns = malloc(sizeof(*mfns) * idx);
+ if ( !mfns )
+ {
+ ERROR("Cannot allocate memory for array of %u mfns", idx);
+ goto err;
+ }
+
+ for ( idx = idx_start; idx <= idx_end; idx++ )
+ {
+ mfn = pte_to_frame(ptes[idx]);
+ if ( mfn == 0 || mfn > ctx->x86_pv.max_mfn )
+ {
+ ERROR("Bad mfn %#lx during page table walk for vaddr %#"
PRIx64 " at level %d of p2m list",
+ mfn, off + ((xen_vaddr_t)idx << shift), level);
+ errno = ERANGE;
+ goto err;
+ }
+ mfns[idx - idx_start] = mfn;
+
+ /* Maximum pfn check at level 2. Same reasoning as for p2m tree. */
+ if ( level == 2 )
+ {
+ if ( mfn != saved_mfn )
+ {
+ saved_mfn = mfn;
+ saved_idx = idx - idx_start;
+ }
+ }
+ }
+
+ if ( level == 2 )
+ {
+ max_pfn = ((xen_pfn_t)saved_idx << 9) * fpp - 1;
+ if ( max_pfn < ctx->x86_pv.max_pfn )
+ {
+ ctx->x86_pv.max_pfn = max_pfn;
+ ctx->x86_pv.p2m_frames = (ctx->x86_pv.max_pfn + fpp) / fpp;
+ p2m_end = p2m_vaddr + ctx->x86_pv.p2m_frames * PAGE_SIZE - 1;
+ idx_end = idx_start + saved_idx;
+ }
+ }
+
+ munmap(ptes, n_pages * PAGE_SIZE);
+ ptes = NULL;
+ off = p2m_vaddr & ((mask >> shift) << shift);
+ }
+
+ /* Map the p2m leaves themselves. */
+ rc = map_p2m_leaves(ctx, mfns, idx_end - idx_start + 1);
+
+err:
+ free(mfns);
+ if ( ptes )
+ munmap(ptes, n_pages * PAGE_SIZE);
+
+ return rc;
+}
+
+/*
+ * Map the guest p2m frames.
+ * Depending on guest support this might either be a virtual mapped linear
+ * list (preferred format) or a 3 level tree linked via mfns.
+ */
+static int map_p2m(struct xc_sr_context *ctx)
+{
+ uint64_t p2m_cr3;
+
+ ctx->x86_pv.max_pfn = GET_FIELD(ctx->x86_pv.shinfo, arch.max_pfn,
+ ctx->x86_pv.width) - 1;
+ p2m_cr3 = GET_FIELD(ctx->x86_pv.shinfo, arch.p2m_cr3, ctx->x86_pv.width);
+
+ return p2m_cr3 ? map_p2m_list(ctx, p2m_cr3) : map_p2m_tree(ctx);
+}
+
+/*
* Obtain a specific vcpus basic state and write an X86_PV_VCPU_BASIC record
* into the stream. Performs mfn->pfn conversion on architectural state.
*/
@@ -681,8 +849,10 @@ static int normalise_pagetable(struct xc_sr_context *ctx,
const uint64_t *src,
/* 64bit guests only have Xen mappings in their L4 tables. */
if ( type == XEN_DOMCTL_PFINFO_L4TAB )
{
- xen_first = 256;
- xen_last = 271;
+ xen_first = (HYPERVISOR_VIRT_START_X86_64 >>
+ L4_PAGETABLE_SHIFT_X86_64) & 511;
+ xen_last = (HYPERVISOR_VIRT_END_X86_64 >>
+ L4_PAGETABLE_SHIFT_X86_64) & 511;
}
}
else
@@ -698,21 +868,19 @@ static int normalise_pagetable(struct xc_sr_context *ctx,
const uint64_t *src,
/* 32bit guests can only use the first 4 entries of their L3
tables.
* All other are potentially used by Xen. */
xen_first = 4;
- xen_last = 512;
+ xen_last = 511;
break;
case XEN_DOMCTL_PFINFO_L2TAB:
/* It is hard to spot Xen mappings in a 32bit guest's L2. Most
* are normal but only a few will have Xen mappings.
- *
- * 428 = (HYPERVISOR_VIRT_START_PAE >>
L2_PAGETABLE_SHIFT_PAE)&0x1ff
- *
- * ...which is conveniently unavailable to us in a 64bit build.
*/
- if ( pte_to_frame(src[428]) == ctx->x86_pv.compat_m2p_mfn0 )
+ i = (HYPERVISOR_VIRT_START_X86_32 >> L2_PAGETABLE_SHIFT_PAE) & 511;
+ if ( pte_to_frame(src[i]) == ctx->x86_pv.compat_m2p_mfn0 )
{
- xen_first = 428;
- xen_last = 512;
+ xen_first = i;
+ xen_last = (HYPERVISOR_VIRT_END_X86_32 >>
+ L2_PAGETABLE_SHIFT_PAE) & 511;
}
break;
}
--
2.6.2
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