Commit: 368a540e0232 (x86/kvmclock: Remove memblock dependency)
caused SEV guest regression. When SEV is active, we map the shared
variables (wall_clock and hv_clock_boot) with C=0 to ensure that both
the guest and the hypervisor are able to access the data. To map the
variables we use kernel_physical_mapping_init() to split the large pages,
but splitting large pages requires allocating a new PMD, which fails now
that kvmclock initialization is called early during boot.
Recently we added a special .data..decrypted section to hold the shared
variables. This section is mapped with C=0 early during boot. Use
__decrypted attribute to put the wall_clock and hv_clock_boot in
.data..decrypted section so that they are mapped with C=0.
Signed-off-by: Brijesh Singh <brijesh.si...@amd.com>
Reviewed-by: Tom Lendacky <thomas.lenda...@amd.com>
Fixes: 368a540e0232 ("x86/kvmclock: Remove memblock dependency")
Cc: Tom Lendacky <thomas.lenda...@amd.com>
Cc: k...@vger.kernel.org
Cc: Thomas Gleixner <t...@linutronix.de>
Cc: Borislav Petkov <b...@suse.de>
Cc: "H. Peter Anvin" <h...@zytor.com>
Cc: linux-kernel@vger.kernel.org
Cc: Paolo Bonzini <pbonz...@redhat.com>
Cc: Sean Christopherson <sean.j.christopher...@intel.com>
Cc: k...@vger.kernel.org
Cc: "Radim Krčmář" <rkrc...@redhat.com>
---
arch/x86/kernel/kvmclock.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
index 1e67646..376fd3a 100644
--- a/arch/x86/kernel/kvmclock.c
+++ b/arch/x86/kernel/kvmclock.c
@@ -61,8 +61,8 @@ early_param("no-kvmclock-vsyscall",
parse_no_kvmclock_vsyscall);
(PAGE_SIZE / sizeof(struct pvclock_vsyscall_time_info))
static struct pvclock_vsyscall_time_info
- hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __aligned(PAGE_SIZE);
-static struct pvclock_wall_clock wall_clock;
+ hv_clock_boot[HVC_BOOT_ARRAY_SIZE] __decrypted
__aligned(PAGE_SIZE);
+static struct pvclock_wall_clock wall_clock __decrypted;
static DEFINE_PER_CPU(struct pvclock_vsyscall_time_info *, hv_clock_per_cpu);
static inline struct pvclock_vcpu_time_info *this_cpu_pvti(void)
--
2.7.4
