arm64/boot: Disable trapping of PMZR_EL0 writes to EL2grafted

__init_el2_fgt2() writes one mask to both HDFGRTR2_EL2 and HDFGWTR2_EL2.
PMZR_EL0 is write-only, so its trap bit, nPMZR_EL0, exists only in
HDFGWTR2_EL2 and is therefore never set: a PMZR_EL0 write from the host
traps to EL2, where the nVHE hypervisor has no handler and BUG()s. The
kernel never writes PMZR_EL0, but kernel.perf_user_access=1 has the PMU
driver set PMUSERENR_EL0.UEN for a task with a user-read event, so a
write from EL0 reaches the trap and takes the host down without a panic
message.

Accumulate the HDFGWTR2_EL2 bits separately, as __init_el2_fgt() already
does for HDFGWTR_EL2, and set nPMZR_EL0 with the other FEAT_PMUv3p9
bits.

Fixes: 858c7bfcb35e1 ("arm64/boot: Enable EL2 requirements for FEAT_PMUv3p9")
Cc: stable@vger.kernel.org
Signed-off-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Reviewed-by: Oliver Upton <oupton@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/include/xen/page.h b/include/xen/page.h
new file mode 100644
index 000000000..285677b42
--- /dev/null
+++ b/include/xen/page.h
@@ -0,0 +1,48 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _XEN_PAGE_H
+#define _XEN_PAGE_H
+
+#include <asm/page.h>
+
+/* The hypercall interface supports only 4KB page */
+#define XEN_PAGE_SHIFT	12
+#define XEN_PAGE_SIZE	(_AC(1, UL) << XEN_PAGE_SHIFT)
+#define XEN_PAGE_MASK	(~(XEN_PAGE_SIZE-1))
+#define xen_offset_in_page(p)	((unsigned long)(p) & ~XEN_PAGE_MASK)
+
+/*
+ * We assume that PAGE_SIZE is a multiple of XEN_PAGE_SIZE
+ * XXX: Add a BUILD_BUG_ON?
+ */
+
+#define xen_pfn_to_page(xen_pfn)	\
+	(pfn_to_page((unsigned long)(xen_pfn) >> (PAGE_SHIFT - XEN_PAGE_SHIFT)))
+#define page_to_xen_pfn(page)		\
+	((page_to_pfn(page)) << (PAGE_SHIFT - XEN_PAGE_SHIFT))
+
+#define XEN_PFN_PER_PAGE	(PAGE_SIZE / XEN_PAGE_SIZE)
+
+#define XEN_PFN_DOWN(x)	((x) >> XEN_PAGE_SHIFT)
+#define XEN_PFN_UP(x)	(((x) + XEN_PAGE_SIZE-1) >> XEN_PAGE_SHIFT)
+
+#include <asm/xen/page.h>
+
+/* Return the GFN associated to the first 4KB of the page */
+static inline unsigned long xen_page_to_gfn(struct page *page)
+{
+	return pfn_to_gfn(page_to_xen_pfn(page));
+}
+
+struct xen_memory_region {
+	unsigned long start_pfn;
+	unsigned long n_pfns;
+};
+
+#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820_MAX_ENTRIES_ZEROPAGE */
+
+extern __initdata
+struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];
+
+extern unsigned long xen_released_pages;
+
+#endif	/* _XEN_PAGE_H */