[PATCH v6 3/6] accel/kvm: Report the loss of a large memory page

“William Roche
2025-01-27T21:31:43Z

From: William Roche <william.roche@oracle.com>

In case of a large page impacted by a memory error, provide an
information about the impacted large page before the memory
error injection message.

This message would also appear on ras enabled ARM platforms, with
the introduction of an x86 similar error injection message.

In the case of a large page impacted, we now report:
Memory Error on large page from <backend>: +<fd_offset> +<page_size>

Signed-off-by: William Roche <william.roche@oracle.com>
---
accel/kvm/kvm-all.c | 11 +++++++++++
include/exec/cpu-common.h | 9 +++++++++
system/physmem.c | 21 +++++++++++++++++++++
target/arm/kvm.c | 3 +++
4 files changed, 44 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index f89568bfa3..08e14f8960 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1296,6 +1296,17 @@ static void kvm_unpoison_all(void *param)
void kvm_hwpoison_page_add(ram_addr_t ram_addr)
{
HWPoisonPage *page;
+ struct RAMBlockInfo rb_info;
+
+ if (qemu_ram_block_location_info_from_addr(ram_addr, &rb_info)) {
+ size_t ps = rb_info.page_size;
+ if (ps > TARGET_PAGE_SIZE) {
+ uint64_t offset = ram_addr - rb_info.offset;
+ error_report("Memory Error on large page from %s:%" PRIx64
+ "+%" PRIx64 " +%zx", rb_info.idstr,
+ QEMU_ALIGN_DOWN(offset, ps), rb_info.fd_offset, ps);
+ }
+ }

QLIST_FOREACH(page, &hwpoison_page_list, list) {
if (page->ram_addr == ram_addr) {
diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h
index 3771b2130c..176537fd80 100644
--- a/include/exec/cpu-common.h
+++ b/include/exec/cpu-common.h
@@ -110,6 +110,15 @@ int qemu_ram_get_fd(RAMBlock *rb);
size_t qemu_ram_pagesize(RAMBlock *block);
size_t qemu_ram_pagesize_largest(void);

+struct RAMBlockInfo {
+ char idstr[256];
+ ram_addr_t offset;
+ uint64_t fd_offset;
+ size_t page_size;
+};
+bool qemu_ram_block_location_info_from_addr(ram_addr_t ram_addr,
+ struct RAMBlockInfo *block);
+
/**
* cpu_address_space_init:
* @cpu: CPU to add this address space to
diff --git a/system/physmem.c b/system/physmem.c
index 3dc10ae27b..c835fef26b 100644
--- a/system/physmem.c
+++ b/system/physmem.c
@@ -1678,6 +1678,27 @@ size_t qemu_ram_pagesize_largest(void)
return largest;
}

+/* Copy RAMBlock information associated to the given ram_addr location */
+bool qemu_ram_block_location_info_from_addr(ram_addr_t ram_addr,
+ struct RAMBlockInfo *b_info)
+{
+ RAMBlock *rb;
+
+ assert(b_info);
+
+ RCU_READ_LOCK_GUARD();
+ rb = qemu_get_ram_block(ram_addr);
+ if (!rb) {
+ return false;
+ }
+
+ pstrcat(b_info->idstr, sizeof(b_info->idstr), rb->idstr);
+ b_info->offset = rb->offset;
+ b_info->fd_offset = rb->fd_offset;
+ b_info->page_size = rb->page_size;
+ return true;
+}
+
static int memory_try_enable_merging(void *addr, size_t len)
{
if (!machine_mem_merge(current_machine)) {
diff --git a/target/arm/kvm.c b/target/arm/kvm.c
index da30bdbb23..d9dedc6d74 100644
--- a/target/arm/kvm.c
+++ b/target/arm/kvm.c
@@ -2389,6 +2389,9 @@ void kvm_arch_on_sigbus_vcpu(CPUState *c, int code, void *addr)
kvm_cpu_synchronize_state(c);
if (!acpi_ghes_memory_errors(ACPI_HEST_SRC_ID_SEA, paddr)) {
kvm_inject_arm_sea(c);
+ error_report("Guest Memory Error at QEMU addr %p and "
+ "GUEST addr 0x%" HWADDR_PRIx " of type %s injected",
+ addr, paddr, "BUS_MCEERR_AR");
} else {
error_report("failed to record the error");
abort();
--
2.43.5