314583a822
5321b20b-common-make-hypercall-preemption-checks-consistent.patch 5321b257-x86-make-hypercall-preemption-checks-consistent.patch 53271880-VT-d-fix-RMRR-handling.patch 5327190a-x86-Intel-work-around-Xeon-7400-series-erratum-AAI65.patch - Dropped the following as now part of 5321b257 5310bac3-mm-ensure-useful-progress-in-decrease_reservation.patch - bnc#867910 - VUL-0: EMBARGOED: xen: XSA-89: HVMOP_set_mem_access is not preemptible xsa89.patch OBS-URL: https://build.opensuse.org/package/show/Virtualization/xen?expand=0&rev=306
97 lines
2.9 KiB
Diff
97 lines
2.9 KiB
Diff
x86: enforce preemption in HVM_set_mem_access / p2m_set_mem_access()
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Processing up to 4G PFNs may take almost arbitrarily long, so
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preemption is needed here.
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This is XSA-89.
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Signed-off-by: Jan Beulich <jbeulich@suse.com>
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Reviewed-by: Tim Deegan <tim@xen.org>
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--- a/xen/arch/x86/hvm/hvm.c
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+++ b/xen/arch/x86/hvm/hvm.c
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@@ -4465,6 +4465,15 @@ long do_hvm_op(unsigned long op, XEN_GUE
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goto param_fail5;
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rc = p2m_set_mem_access(d, a.first_pfn, a.nr, a.hvmmem_access);
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+ if ( rc > 0 )
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+ {
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+ a.first_pfn += a.nr - rc;
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+ a.nr = rc;
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+ if ( __copy_to_guest(arg, &a, 1) )
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+ rc = -EFAULT;
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+ else
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+ rc = -EAGAIN;
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+ }
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param_fail5:
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rcu_unlock_domain(d);
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--- a/xen/arch/x86/mm/p2m.c
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+++ b/xen/arch/x86/mm/p2m.c
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@@ -1366,15 +1366,14 @@ void p2m_mem_access_resume(struct domain
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/* Set access type for a region of pfns.
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* If start_pfn == -1ul, sets the default access type */
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-int p2m_set_mem_access(struct domain *d, unsigned long start_pfn,
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- uint32_t nr, hvmmem_access_t access)
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+long p2m_set_mem_access(struct domain *d, unsigned long pfn, uint32_t nr,
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+ hvmmem_access_t access)
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{
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struct p2m_domain *p2m = p2m_get_hostp2m(d);
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- unsigned long pfn;
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p2m_access_t a, _a;
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p2m_type_t t;
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mfn_t mfn;
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- int rc = 0;
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+ long rc;
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/* N.B. _not_ static: initializer depends on p2m->default_access */
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p2m_access_t memaccess[] = {
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@@ -1397,14 +1396,17 @@ int p2m_set_mem_access(struct domain *d,
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a = memaccess[access];
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/* If request to set default access */
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- if ( start_pfn == ~0ull )
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+ if ( pfn == ~0ul )
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{
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p2m->default_access = a;
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return 0;
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}
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+ if ( !nr )
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+ return 0;
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+
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p2m_lock(p2m);
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- for ( pfn = start_pfn; pfn < start_pfn + nr; pfn++ )
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+ for ( ; ; ++pfn )
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{
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mfn = p2m->get_entry(p2m, pfn, &t, &_a, 0, NULL);
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if ( p2m->set_entry(p2m, pfn, mfn, PAGE_ORDER_4K, t, a) == 0 )
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@@ -1412,6 +1414,13 @@ int p2m_set_mem_access(struct domain *d,
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rc = -ENOMEM;
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break;
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}
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+
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+ /* Check for continuation if it's not the last interation. */
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+ if ( !--nr || hypercall_preempt_check() )
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+ {
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+ rc = nr;
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+ break;
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+ }
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}
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p2m_unlock(p2m);
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return rc;
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--- a/xen/include/asm-x86/p2m.h
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+++ b/xen/include/asm-x86/p2m.h
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@@ -576,8 +576,8 @@ void p2m_mem_access_resume(struct domain
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/* Set access type for a region of pfns.
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* If start_pfn == -1ul, sets the default access type */
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-int p2m_set_mem_access(struct domain *d, unsigned long start_pfn,
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- uint32_t nr, hvmmem_access_t access);
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+long p2m_set_mem_access(struct domain *d, unsigned long start_pfn,
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+ uint32_t nr, hvmmem_access_t access);
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/* Get access type for a pfn
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* If pfn == -1ul, gets the default access type */
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