[PATCH 07/15] KVM: x86/mmu: Implement PWALK_SET_DIRTY in page walker

Nikolas Wipper
2024-09-10T15:24:20Z

Implement PWALK_SET_DIRTY in the page walker. This flag allows controlling,
whether the page walker will set the dirty bit after a successful page
walk. If the page walk fails for any reason, the dirty flag is not set.

Signed-off-by: Nikolas Wipper <nikwip@amazon.de>
---
arch/x86/kvm/mmu/paging_tmpl.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kvm/mmu/paging_tmpl.h b/arch/x86/kvm/mmu/paging_tmpl.h
index eed6e2c653ba..b6897f7fbf52 100644
--- a/arch/x86/kvm/mmu/paging_tmpl.h
+++ b/arch/x86/kvm/mmu/paging_tmpl.h
@@ -318,6 +318,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,
const int user_fault = access & PFERR_USER_MASK;
const int fetch_fault = access & PFERR_FETCH_MASK;
const int set_accessed = flags & PWALK_SET_ACCESSED;
+ const int set_dirty = flags & PWALK_SET_DIRTY;
u16 errcode = 0;
gpa_t real_gpa;
gfn_t gfn;
@@ -471,7 +472,7 @@ static int FNAME(walk_addr_generic)(struct guest_walker *walker,

if (unlikely(set_accessed && !accessed_dirty)) {
ret = FNAME(update_accessed_dirty_bits)(vcpu, mmu, walker, addr,
- write_fault);
+ write_fault && set_dirty);
if (unlikely(ret < 0))
goto error;
else if (ret)