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sev/utils: Use iterator combinators for pvalidate and RMP revoke paths #915

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Merged
joergroedel merged 2 commits into from
Jan 27, 2026
Merged

sev/utils: Use iterator combinators for pvalidate and RMP revoke paths #915

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e710438
sev/utils: Use iterator combinators for pvalidate and RMP revoke paths
v-thakkar Dec 5, 2025
3bbe429
sev/utils: Improve error handling for pvalidate callers
v-thakkar Jan 26, 2026
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43 changes: 27 additions & 16 deletions kernel/src/sev/utils.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,16 @@ impl SevSnpError {
| Self::FAIL_SIZEMISMATCH(ret) => *ret,
}
}

fn with_addr(self, addr: VirtAddr) -> Self {
let vaddr = addr.bits() as u64;
match self {
Self::FAIL_INPUT(_) => Self::FAIL_INPUT(vaddr),
Self::FAIL_PERMISSION(_) => Self::FAIL_PERMISSION(vaddr),
Self::FAIL_SIZEMISMATCH(_) => Self::FAIL_SIZEMISMATCH(vaddr),
Self::FAIL_UNCHANGED(_) => Self::FAIL_UNCHANGED(vaddr),
}
}
}

impl fmt::Display for SevSnpError {
Expand All @@ -59,14 +69,15 @@ unsafe fn pvalidate_range_4k(
region: MemoryRegion<VirtAddr>,
valid: PvalidateOp,
) -> Result<(), SvsmError> {
for addr in region.iter_pages(PageSize::Regular) {
region
.iter_pages(PageSize::Regular)
// SAFETY: the caller promises that the validation operation is safe.
unsafe {
pvalidate(addr, PageSize::Regular, valid)?;
}
}

Ok(())
.try_for_each(|addr| unsafe {
pvalidate(addr, PageSize::Regular, valid).map_err(|e| match e {
SvsmError::SevSnp(err) => err.with_addr(addr).into(),
other => other,
})
})
}

/// # Safety
Expand Down Expand Up @@ -95,15 +106,19 @@ pub unsafe fn pvalidate_range(
SvsmError::SevSnp(SevSnpError::FAIL_SIZEMISMATCH(_)) => {
pvalidate_range_4k(MemoryRegion::new(addr, PAGE_SIZE_2M), valid)
}
_ => Err(err),
SvsmError::SevSnp(e) => Err(e.with_addr(addr).into()),
other => Err(other),
})?;
}
addr = addr + PAGE_SIZE_2M;
} else {
// SAFETY: the caller promises that the validation operation is
// safe.
unsafe {
pvalidate(addr, PageSize::Regular, valid)?;
pvalidate(addr, PageSize::Regular, valid).map_err(|e| match e {
SvsmError::SevSnp(err) => err.with_addr(addr).into(),
other => other,
})?;
}
addr = addr + PAGE_SIZE;
}
Expand Down Expand Up @@ -288,14 +303,10 @@ pub unsafe fn rmp_adjust(addr: VirtAddr, flags: RMPFlags, size: PageSize) -> Res
}

pub fn rmp_revoke_guest_access(vaddr: VirtAddr, size: PageSize) -> Result<(), SvsmError> {
for vmpl in RMPFlags::GUEST_VMPL.bits()..=RMPFlags::VMPL3.bits() {
let vmpl = RMPFlags::from_bits_truncate(vmpl);
(RMPFlags::GUEST_VMPL.bits()..=RMPFlags::VMPL3.bits())
.map(RMPFlags::from_bits_truncate)
// SAFETY: revoking guest access can never affect memory safety.
unsafe {
rmp_adjust(vaddr, vmpl | RMPFlags::NONE, size)?;
}
}
Ok(())
.try_for_each(|vmpl| unsafe { rmp_adjust(vaddr, vmpl | RMPFlags::NONE, size) })
}

/// # Safety
Expand Down