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[PATCH 2/6] hyper-v: Use -1 as invalid overlay address
From: |
Siddharth Chandrasekaran |
Subject: |
[PATCH 2/6] hyper-v: Use -1 as invalid overlay address |
Date: |
Mon, 24 May 2021 21:54:05 +0200 |
When managing overlay pages, we used hwaddr 0 to signal an invalid
address (to disable a page). Although unlikely, 0 _could_ be a valid
overlay offset as Hyper-V TLFS does not specify anything about it.
Use -1 as the invalid address indicator as it can never be a valid
address.
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
---
hw/hyperv/hyperv.c | 15 +++++++++------
include/hw/hyperv/hyperv.h | 1 +
2 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/hw/hyperv/hyperv.c b/hw/hyperv/hyperv.c
index 8d09206702..ac45e8e139 100644
--- a/hw/hyperv/hyperv.c
+++ b/hw/hyperv/hyperv.c
@@ -43,7 +43,7 @@ static void alloc_overlay_page(struct hyperv_overlay_page
*overlay,
memory_region_init_ram(&overlay->mr, owner, name,
qemu_real_host_page_size, &error_abort);
overlay->ram_ptr = memory_region_get_ram_ptr(&overlay->mr);
- overlay->addr = 0;
+ overlay->addr = HYPERV_INVALID_OVERLAY_GPA;
}
/**
@@ -52,14 +52,17 @@ static void alloc_overlay_page(struct hyperv_overlay_page
*overlay,
*/
static void hyperv_overlay_update(struct hyperv_overlay_page *overlay, hwaddr
addr)
{
- /* check if overlay page is enabled */
- addr = (addr & HYPERV_OVERLAY_ENABLED) ? (addr & TARGET_PAGE_MASK) : 0;
+ if (addr != HYPERV_INVALID_OVERLAY_GPA) {
+ /* check if overlay page is enabled */
+ addr = (addr & HYPERV_OVERLAY_ENABLED) ?
+ (addr & TARGET_PAGE_MASK) : HYPERV_INVALID_OVERLAY_GPA;
+ }
if (overlay->addr != addr) {
- if (overlay->addr) {
+ if (overlay->addr != HYPERV_INVALID_OVERLAY_GPA) {
memory_region_del_subregion(get_system_memory(), &overlay->mr);
}
- if (addr) {
+ if (addr != HYPERV_INVALID_OVERLAY_GPA) {
memory_region_add_subregion(get_system_memory(), addr,
&overlay->mr);
overlay->ram_ptr = memory_region_get_ram_ptr(&overlay->mr);
}
@@ -121,7 +124,7 @@ static void synic_reset(DeviceState *dev)
SynICState *synic = SYNIC(dev);
memset(synic->msg_page.ram_ptr, 0, sizeof(struct hyperv_message_page));
memset(synic->event_page.ram_ptr, 0, sizeof(struct
hyperv_event_flags_page));
- synic_update(synic, false, 0, 0);
+ synic_update(synic, false, HYPERV_INVALID_OVERLAY_GPA,
HYPERV_INVALID_OVERLAY_GPA);
}
static void synic_class_init(ObjectClass *klass, void *data)
diff --git a/include/hw/hyperv/hyperv.h b/include/hw/hyperv/hyperv.h
index 3b2e0093b5..d989193e84 100644
--- a/include/hw/hyperv/hyperv.h
+++ b/include/hw/hyperv/hyperv.h
@@ -15,6 +15,7 @@
#include "exec/memory.h"
#define HYPERV_OVERLAY_ENABLED (1u << 0)
+#define HYPERV_INVALID_OVERLAY_GPA ((hwaddr)-1)
struct hyperv_overlay_page {
hwaddr addr;
--
2.17.1
Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879
- [PATCH 0/6] Handle hypercall code overlay page in userspace, Siddharth Chandrasekaran, 2021/05/24
- [PATCH 1/6] hyper-v: Overlay abstraction for synic event and msg pages, Siddharth Chandrasekaran, 2021/05/24
- [PATCH 3/6] kvm/i386: Stop using cpu->kvm_msr_buf in kvm_put_one_msr(), Siddharth Chandrasekaran, 2021/05/24
- [PATCH 2/6] hyper-v: Use -1 as invalid overlay address,
Siddharth Chandrasekaran <=
- [PATCH 4/6] kvm/i386: Avoid multiple calls to check_extension(KVM_CAP_HYPERV), Siddharth Chandrasekaran, 2021/05/24
- [PATCH 5/6] kvm/i386: Add support for user space MSR filtering, Siddharth Chandrasekaran, 2021/05/24
- [PATCH 6/6] hyper-v: Handle hypercall code page as an overlay page, Siddharth Chandrasekaran, 2021/05/24