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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 1 of 3] Ensure maps used by nested hvm code cannot be paged out
xen/arch/x86/hvm/hvm.c | 69 ++++++++++++++++++++++++-------------
xen/arch/x86/hvm/nestedhvm.c | 4 +-
xen/arch/x86/hvm/svm/nestedsvm.c | 23 ++++++------
xen/arch/x86/hvm/vmx/vvmx.c | 36 +++++++++++--------
xen/include/asm-x86/hvm/hvm.h | 9 +++-
xen/include/asm-x86/hvm/vcpu.h | 1 +
xen/include/asm-x86/hvm/vmx/vvmx.h | 1 +
7 files changed, 88 insertions(+), 55 deletions(-)
The nested hvm code maps pages of the guest hvm. These maps live beyond
a hypervisor entry/exit pair, and thus their liveness cannot be ensured
with get_gfn/put_gfn critical sections. Ensure their liveness by
increasing the page ref count, instead.
Signed-off-by: Andres Lagar-Cavilla <andres@xxxxxxxxxxxxxxxx>
diff -r a64f63ecfc57 -r f079cbeae77e xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c
+++ b/xen/arch/x86/hvm/hvm.c
@@ -1801,11 +1801,15 @@ int hvm_virtual_to_linear_addr(
return 0;
}
-/* We leave this function holding a lock on the p2m entry */
-static void *__hvm_map_guest_frame(unsigned long gfn, bool_t writable)
+/* On non-NULL return, we leave this function holding an additional
+ * ref on the underlying mfn, if any */
+static void *__hvm_map_guest_frame(unsigned long gfn, bool_t writable,
+ struct page_info **page)
{
+ void *map;
unsigned long mfn;
p2m_type_t p2mt;
+ struct page_info *pg;
struct domain *d = current->domain;
mfn = mfn_x(writable
@@ -1828,27 +1832,43 @@ static void *__hvm_map_guest_frame(unsig
if ( writable )
paging_mark_dirty(d, mfn);
- return map_domain_page(mfn);
+ pg = mfn_to_page(mfn);
+ if (page)
+ {
+ page_get_owner_and_reference(pg);
+ *page = pg;
+ }
+
+ map = map_domain_page(mfn);
+ put_gfn(d, gfn);
+ return map;
}
-void *hvm_map_guest_frame_rw(unsigned long gfn)
+void *hvm_map_guest_frame_rw(unsigned long gfn,
+ struct page_info **page)
{
- return __hvm_map_guest_frame(gfn, 1);
+ return __hvm_map_guest_frame(gfn, 1, page);
}
-void *hvm_map_guest_frame_ro(unsigned long gfn)
+void *hvm_map_guest_frame_ro(unsigned long gfn,
+ struct page_info **page)
{
- return __hvm_map_guest_frame(gfn, 0);
+ return __hvm_map_guest_frame(gfn, 0, page);
}
-void hvm_unmap_guest_frame(void *p)
+void hvm_unmap_guest_frame(void *p, struct page_info *page)
{
if ( p )
+ {
unmap_domain_page(p);
+ if ( page )
+ put_page(page);
+ }
}
-static void *hvm_map_entry(unsigned long va, unsigned long *gfn)
+static void *hvm_map_entry(unsigned long va, struct page_info **page)
{
+ unsigned long gfn;
uint32_t pfec;
char *v;
@@ -1865,11 +1885,11 @@ static void *hvm_map_entry(unsigned long
* treat it as a kernel-mode read (i.e. no access checks).
*/
pfec = PFEC_page_present;
- *gfn = paging_gva_to_gfn(current, va, &pfec);
+ gfn = paging_gva_to_gfn(current, va, &pfec);
if ( (pfec == PFEC_page_paged) || (pfec == PFEC_page_shared) )
goto fail;
- v = hvm_map_guest_frame_rw(*gfn);
+ v = hvm_map_guest_frame_rw(gfn, page);
if ( v == NULL )
goto fail;
@@ -1880,11 +1900,9 @@ static void *hvm_map_entry(unsigned long
return NULL;
}
-static void hvm_unmap_entry(void *p, unsigned long gfn)
+static void hvm_unmap_entry(void *p, struct page_info *page)
{
- hvm_unmap_guest_frame(p);
- if ( p && (gfn != INVALID_GFN) )
- put_gfn(current->domain, gfn);
+ hvm_unmap_guest_frame(p, page);
}
static int hvm_load_segment_selector(
@@ -1896,7 +1914,7 @@ static int hvm_load_segment_selector(
int fault_type = TRAP_invalid_tss;
struct cpu_user_regs *regs = guest_cpu_user_regs();
struct vcpu *v = current;
- unsigned long pdesc_gfn = INVALID_GFN;
+ struct page_info *pdesc_pg = NULL;
if ( regs->eflags & X86_EFLAGS_VM )
{
@@ -1930,7 +1948,7 @@ static int hvm_load_segment_selector(
if ( ((sel & 0xfff8) + 7) > desctab.limit )
goto fail;
- pdesc = hvm_map_entry(desctab.base + (sel & 0xfff8), &pdesc_gfn);
+ pdesc = hvm_map_entry(desctab.base + (sel & 0xfff8), &pdesc_pg);
if ( pdesc == NULL )
goto hvm_map_fail;
@@ -1990,7 +2008,7 @@ static int hvm_load_segment_selector(
desc.b |= 0x100;
skip_accessed_flag:
- hvm_unmap_entry(pdesc, pdesc_gfn);
+ hvm_unmap_entry(pdesc, pdesc_pg);
segr.base = (((desc.b << 0) & 0xff000000u) |
((desc.b << 16) & 0x00ff0000u) |
@@ -2006,7 +2024,7 @@ static int hvm_load_segment_selector(
return 0;
unmap_and_fail:
- hvm_unmap_entry(pdesc, pdesc_gfn);
+ hvm_unmap_entry(pdesc, pdesc_pg);
fail:
hvm_inject_exception(fault_type, sel & 0xfffc, 0);
hvm_map_fail:
@@ -2021,7 +2039,8 @@ void hvm_task_switch(
struct cpu_user_regs *regs = guest_cpu_user_regs();
struct segment_register gdt, tr, prev_tr, segr;
struct desc_struct *optss_desc = NULL, *nptss_desc = NULL, tss_desc;
- unsigned long eflags, optss_gfn = INVALID_GFN, nptss_gfn = INVALID_GFN;
+ unsigned long eflags;
+ struct page_info *optss_pg = NULL, *nptss_pg = NULL;
int exn_raised, rc;
struct {
u16 back_link,__blh;
@@ -2047,11 +2066,13 @@ void hvm_task_switch(
goto out;
}
- optss_desc = hvm_map_entry(gdt.base + (prev_tr.sel & 0xfff8), &optss_gfn);
+ optss_desc = hvm_map_entry(gdt.base + (prev_tr.sel & 0xfff8),
+ &optss_pg);
if ( optss_desc == NULL )
goto out;
- nptss_desc = hvm_map_entry(gdt.base + (tss_sel & 0xfff8), &nptss_gfn);
+ nptss_desc = hvm_map_entry(gdt.base + (tss_sel & 0xfff8),
+ &nptss_pg);
if ( nptss_desc == NULL )
goto out;
@@ -2216,8 +2237,8 @@ void hvm_task_switch(
}
out:
- hvm_unmap_entry(optss_desc, optss_gfn);
- hvm_unmap_entry(nptss_desc, nptss_gfn);
+ hvm_unmap_entry(optss_desc, optss_pg);
+ hvm_unmap_entry(nptss_desc, nptss_pg);
}
#define HVMCOPY_from_guest (0u<<0)
diff -r a64f63ecfc57 -r f079cbeae77e xen/arch/x86/hvm/nestedhvm.c
--- a/xen/arch/x86/hvm/nestedhvm.c
+++ b/xen/arch/x86/hvm/nestedhvm.c
@@ -56,9 +56,11 @@ nestedhvm_vcpu_reset(struct vcpu *v)
nv->nv_ioportED = 0;
if (nv->nv_vvmcx)
- hvm_unmap_guest_frame(nv->nv_vvmcx);
+ hvm_unmap_guest_frame(nv->nv_vvmcx,
+ nv->nv_vvmcx_pg);
nv->nv_vvmcx = NULL;
nv->nv_vvmcxaddr = VMCX_EADDR;
+ nv->nv_vvmcx_pg = NULL;
nv->nv_flushp2m = 0;
nv->nv_p2m = NULL;
diff -r a64f63ecfc57 -r f079cbeae77e xen/arch/x86/hvm/svm/nestedsvm.c
--- a/xen/arch/x86/hvm/svm/nestedsvm.c
+++ b/xen/arch/x86/hvm/svm/nestedsvm.c
@@ -71,20 +71,18 @@ int nestedsvm_vmcb_map(struct vcpu *v, u
if (nv->nv_vvmcx != NULL && nv->nv_vvmcxaddr != vmcbaddr) {
ASSERT(nv->nv_vvmcx != NULL);
ASSERT(nv->nv_vvmcxaddr != VMCX_EADDR);
- hvm_unmap_guest_frame(nv->nv_vvmcx);
+ hvm_unmap_guest_frame(nv->nv_vvmcx, nv->nv_vvmcx_pg);
nv->nv_vvmcx = NULL;
nv->nv_vvmcxaddr = VMCX_EADDR;
+ nv->nv_vvmcx_pg = NULL;
}
if (nv->nv_vvmcx == NULL) {
- nv->nv_vvmcx = hvm_map_guest_frame_rw(vmcbaddr >> PAGE_SHIFT);
+ nv->nv_vvmcx = hvm_map_guest_frame_rw(vmcbaddr >> PAGE_SHIFT,
+ &nv->nv_vvmcx_pg);
if (nv->nv_vvmcx == NULL)
return 0;
nv->nv_vvmcxaddr = vmcbaddr;
- /* put_gfn here even though the map survives beyond this caller.
- * The map can likely survive beyond a hypervisor exit, thus we
- * need to put the gfn */
- put_gfn(current->domain, vmcbaddr >> PAGE_SHIFT);
}
return 1;
@@ -336,6 +334,7 @@ static int nsvm_vmrun_permissionmap(stru
unsigned int i;
enum hvm_copy_result ret;
unsigned long *ns_viomap;
+ struct page_info *ns_viomap_pg = NULL;
bool_t ioport_80, ioport_ed;
ns_msrpm_ptr = (unsigned long *)svm->ns_cached_msrpm;
@@ -353,12 +352,12 @@ static int nsvm_vmrun_permissionmap(stru
svm->ns_oiomap_pa = svm->ns_iomap_pa;
svm->ns_iomap_pa = ns_vmcb->_iopm_base_pa;
- ns_viomap = hvm_map_guest_frame_ro(svm->ns_iomap_pa >> PAGE_SHIFT);
+ ns_viomap = hvm_map_guest_frame_ro(svm->ns_iomap_pa >> PAGE_SHIFT,
+ &ns_viomap_pg);
ASSERT(ns_viomap != NULL);
ioport_80 = test_bit(0x80, ns_viomap);
ioport_ed = test_bit(0xed, ns_viomap);
- hvm_unmap_guest_frame(ns_viomap);
- put_gfn(current->domain, svm->ns_iomap_pa >> PAGE_SHIFT);
+ hvm_unmap_guest_frame(ns_viomap, ns_viomap_pg);
svm->ns_iomap = nestedhvm_vcpu_iomap_get(ioport_80, ioport_ed);
@@ -863,6 +862,7 @@ nsvm_vmcb_guest_intercepts_ioio(paddr_t
uint16_t port;
bool_t enabled;
unsigned long gfn = 0; /* gcc ... */
+ struct page_info *io_bitmap_pg = NULL;
ioinfo.bytes = exitinfo1;
port = ioinfo.fields.port;
@@ -880,7 +880,7 @@ nsvm_vmcb_guest_intercepts_ioio(paddr_t
break;
}
- io_bitmap = hvm_map_guest_frame_ro(gfn);
+ io_bitmap = hvm_map_guest_frame_ro(gfn, &io_bitmap_pg);
if (io_bitmap == NULL) {
gdprintk(XENLOG_ERR,
"IOIO intercept: mapping of permission map failed\n");
@@ -888,8 +888,7 @@ nsvm_vmcb_guest_intercepts_ioio(paddr_t
}
enabled = test_bit(port, io_bitmap);
- hvm_unmap_guest_frame(io_bitmap);
- put_gfn(current->domain, gfn);
+ hvm_unmap_guest_frame(io_bitmap, io_bitmap_pg);
if (!enabled)
return NESTEDHVM_VMEXIT_HOST;
diff -r a64f63ecfc57 -r f079cbeae77e xen/arch/x86/hvm/vmx/vvmx.c
--- a/xen/arch/x86/hvm/vmx/vvmx.c
+++ b/xen/arch/x86/hvm/vmx/vvmx.c
@@ -44,10 +44,13 @@ int nvmx_vcpu_initialise(struct vcpu *v)
nvmx->vmxon_region_pa = 0;
nvcpu->nv_vvmcx = NULL;
nvcpu->nv_vvmcxaddr = VMCX_EADDR;
+ nvcpu->nv_vvmcx_pg = NULL;
nvmx->intr.intr_info = 0;
nvmx->intr.error_code = 0;
nvmx->iobitmap[0] = NULL;
nvmx->iobitmap[1] = NULL;
+ nvmx->iobitmap_pg[0] = NULL;
+ nvmx->iobitmap_pg[1] = NULL;
return 0;
out:
return -ENOMEM;
@@ -558,12 +561,14 @@ static void __map_io_bitmap(struct vcpu
index = vmcs_reg == IO_BITMAP_A ? 0 : 1;
if (nvmx->iobitmap[index])
- hvm_unmap_guest_frame (nvmx->iobitmap[index]);
+ {
+ hvm_unmap_guest_frame (nvmx->iobitmap[index],
+ nvmx->iobitmap_pg[index]);
+ nvmx->iobitmap_pg[index] = NULL;
+ }
gpa = __get_vvmcs(vcpu_nestedhvm(v).nv_vvmcx, vmcs_reg);
- nvmx->iobitmap[index] = hvm_map_guest_frame_ro (gpa >> PAGE_SHIFT);
- /* See comment in nestedsvm_vmcb_map re putting this gfn and
- * liveness of the map it backs */
- put_gfn(current->domain, gpa >> PAGE_SHIFT);
+ nvmx->iobitmap[index] = hvm_map_guest_frame_ro(gpa >> PAGE_SHIFT,
+ &nvmx->iobitmap_pg[index]);
}
static inline void map_io_bitmap_all(struct vcpu *v)
@@ -580,13 +585,16 @@ static void nvmx_purge_vvmcs(struct vcpu
__clear_current_vvmcs(v);
if ( nvcpu->nv_vvmcxaddr != VMCX_EADDR )
- hvm_unmap_guest_frame(nvcpu->nv_vvmcx);
- nvcpu->nv_vvmcx == NULL;
+ hvm_unmap_guest_frame(nvcpu->nv_vvmcx, nvcpu->nv_vvmcx_pg);
+ nvcpu->nv_vvmcx = NULL;
nvcpu->nv_vvmcxaddr = VMCX_EADDR;
+ nvcpu->nv_vvmcx_pg = NULL;
for (i=0; i<2; i++) {
if ( nvmx->iobitmap[i] ) {
- hvm_unmap_guest_frame(nvmx->iobitmap[i]);
+ hvm_unmap_guest_frame(nvmx->iobitmap[i],
+ nvmx->iobitmap_pg[i]);
nvmx->iobitmap[i] = NULL;
+ nvmx->iobitmap_pg[i] = NULL;
}
}
}
@@ -1138,12 +1146,10 @@ int nvmx_handle_vmptrld(struct cpu_user_
if ( nvcpu->nv_vvmcxaddr == VMCX_EADDR )
{
- nvcpu->nv_vvmcx = hvm_map_guest_frame_rw (gpa >> PAGE_SHIFT);
+ nvcpu->nv_vvmcx = hvm_map_guest_frame_rw(gpa >> PAGE_SHIFT,
+ &nvcpu->nv_vvmcx_pg);
nvcpu->nv_vvmcxaddr = gpa;
map_io_bitmap_all (v);
- /* See comment in nestedsvm_vmcb_map regarding putting this
- * gfn and liveness of the map that uses it */
- put_gfn(current->domain, gpa >> PAGE_SHIFT);
}
vmreturn(regs, VMSUCCEED);
@@ -1201,11 +1207,11 @@ int nvmx_handle_vmclear(struct cpu_user_
else
{
/* Even if this VMCS isn't the current one, we must clear it. */
- vvmcs = hvm_map_guest_frame_rw(gpa >> PAGE_SHIFT);
+ struct page_info *vvmcs_pg = NULL;
+ vvmcs = hvm_map_guest_frame_rw(gpa >> PAGE_SHIFT, &vvmcs_pg);
if ( vvmcs )
__set_vvmcs(vvmcs, NVMX_LAUNCH_STATE, 0);
- hvm_unmap_guest_frame(vvmcs);
- put_gfn(current->domain, gpa >> PAGE_SHIFT);
+ hvm_unmap_guest_frame(vvmcs, vvmcs_pg);
}
vmreturn(regs, VMSUCCEED);
diff -r a64f63ecfc57 -r f079cbeae77e xen/include/asm-x86/hvm/hvm.h
--- a/xen/include/asm-x86/hvm/hvm.h
+++ b/xen/include/asm-x86/hvm/hvm.h
@@ -26,6 +26,7 @@
#include <asm/hvm/asid.h>
#include <public/domctl.h>
#include <public/hvm/save.h>
+#include <asm/mm.h>
/* Interrupt acknowledgement sources. */
enum hvm_intsrc {
@@ -392,9 +393,11 @@ int hvm_virtual_to_linear_addr(
unsigned int addr_size,
unsigned long *linear_addr);
-void *hvm_map_guest_frame_rw(unsigned long gfn);
-void *hvm_map_guest_frame_ro(unsigned long gfn);
-void hvm_unmap_guest_frame(void *p);
+void *hvm_map_guest_frame_rw(unsigned long gfn,
+ struct page_info **page);
+void *hvm_map_guest_frame_ro(unsigned long gfn,
+ struct page_info **page);
+void hvm_unmap_guest_frame(void *p, struct page_info *page);
static inline void hvm_set_info_guest(struct vcpu *v)
{
diff -r a64f63ecfc57 -r f079cbeae77e xen/include/asm-x86/hvm/vcpu.h
--- a/xen/include/asm-x86/hvm/vcpu.h
+++ b/xen/include/asm-x86/hvm/vcpu.h
@@ -77,6 +77,7 @@ struct nestedvcpu {
void *nv_n2vmcx; /* shadow VMCB/VMCS used to run l2 guest */
uint64_t nv_vvmcxaddr; /* l1 guest physical address of nv_vvmcx */
+ struct page_info *nv_vvmcx_pg; /* page where nv_vvmcx resides */
uint64_t nv_n1vmcx_pa; /* host physical address of nv_n1vmcx */
uint64_t nv_n2vmcx_pa; /* host physical address of nv_n2vmcx */
diff -r a64f63ecfc57 -r f079cbeae77e xen/include/asm-x86/hvm/vmx/vvmx.h
--- a/xen/include/asm-x86/hvm/vmx/vvmx.h
+++ b/xen/include/asm-x86/hvm/vmx/vvmx.h
@@ -26,6 +26,7 @@
struct nestedvmx {
paddr_t vmxon_region_pa;
void *iobitmap[2]; /* map (va) of L1 guest I/O bitmap */
+ struct page_info *iobitmap_pg[2]; /* pages backing L1 guest I/O bitmap */
/* deferred nested interrupt */
struct {
unsigned long intr_info;
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