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| author | Juergen Gross <jgross@suse.com> | 2018-08-21 17:37:54 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-09-15 09:45:35 +0200 |
| commit | 13b23ccfa28811333b866196e38d0bc35f68240d (patch) | |
| tree | b407bd63a6729dff31608929f0ff511f74eebd57 /arch | |
| parent | d85c2999a7b5e924172f0cc21f5804bbb1f34d69 (diff) | |
| download | linux-exynos-13b23ccfa28811333b866196e38d0bc35f68240d.tar.gz linux-exynos-13b23ccfa28811333b866196e38d0bc35f68240d.tar.bz2 linux-exynos-13b23ccfa28811333b866196e38d0bc35f68240d.zip | |
x86/xen: don't write ptes directly in 32-bit PV guests
commit f7c90c2aa4004808dff777ba6ae2c7294dd06851 upstream.
In some cases 32-bit PAE PV guests still write PTEs directly instead of
using hypercalls. This is especially bad when clearing a PTE as this is
done via 32-bit writes which will produce intermediate L1TF attackable
PTEs.
Change the code to use hypercalls instead.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/xen/mmu_pv.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/arch/x86/xen/mmu_pv.c b/arch/x86/xen/mmu_pv.c index b3526a98a5a5..42cfad67b6ac 100644 --- a/arch/x86/xen/mmu_pv.c +++ b/arch/x86/xen/mmu_pv.c @@ -425,14 +425,13 @@ static void xen_set_pud(pud_t *ptr, pud_t val) static void xen_set_pte_atomic(pte_t *ptep, pte_t pte) { trace_xen_mmu_set_pte_atomic(ptep, pte); - set_64bit((u64 *)ptep, native_pte_val(pte)); + __xen_set_pte(ptep, pte); } static void xen_pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) { trace_xen_mmu_pte_clear(mm, addr, ptep); - if (!xen_batched_set_pte(ptep, native_make_pte(0))) - native_pte_clear(mm, addr, ptep); + __xen_set_pte(ptep, native_make_pte(0)); } static void xen_pmd_clear(pmd_t *pmdp) @@ -1543,7 +1542,7 @@ static void __init xen_set_pte_init(pte_t *ptep, pte_t pte) pte = __pte_ma(((pte_val_ma(*ptep) & _PAGE_RW) | ~_PAGE_RW) & pte_val_ma(pte)); #endif - native_set_pte(ptep, pte); + __xen_set_pte(ptep, pte); } /* Early in boot, while setting up the initial pagetable, assume |