openhcl/loader: move snp specific pages to new vtl2 reserved region

openhcl/bootloader_fdt_parser/src/lib.rs

@@ -158,6 +158,8 @@ pub struct ParsedBootDtInfo {
     /// The ranges config regions are stored at.
     #[inspect(iter_by_index)]
     pub config_ranges: Vec<MemoryRange>,
+    /// The VTL2 reserved range.
+    pub vtl2_reserved_range: MemoryRange,
     /// The ranges that were accepted at load time by the host on behalf of the
     /// guest.
     #[inspect(iter_by_index)]
@@ -201,6 +203,7 @@ struct OpenhclInfo {
     config_ranges: Vec<MemoryRange>,
     partition_memory_map: Vec<AddressRange>,
     accepted_memory: Vec<MemoryRange>,
+    vtl2_reserved_range: MemoryRange,
     vtl0_alias_map: Option<u64>,
     memory_allocation_mode: MemoryAllocationMode,
     isolation: IsolationType,
@@ -352,6 +355,25 @@ fn parse_openhcl(node: &Node<'_>) -> anyhow::Result<OpenhclInfo> {
         })
         .collect();
 
+    // Report the reserved range. There should only be one.
+    let vtl2_reserved_range = {
+        let mut reserved_range_iter = memory.iter().filter_map(|entry| {
+            if entry.vtl_usage() == MemoryVtlType::VTL2_RESERVED {
+                Some(*entry.range())
+            } else {
+                None
+            }
+        });
+
+        let reserved_range = reserved_range_iter.next().unwrap_or(MemoryRange::EMPTY);
+
+        if reserved_range_iter.next().is_some() {
+            bail!("multiple VTL2 reserved ranges found");
+        }
+
+        reserved_range
+    };
+
     let vtl0_alias_map = try_find_property(node, "vtl0-alias-map")
         .map(|prop| prop.read_u64(0).map_err(err_to_owned))
         .transpose()
@@ -374,6 +396,7 @@ fn parse_openhcl(node: &Node<'_>) -> anyhow::Result<OpenhclInfo> {
         config_ranges,
         partition_memory_map: memory,
         accepted_memory,
+        vtl2_reserved_range,
         vtl0_alias_map,
         memory_allocation_mode,
         isolation,
@@ -469,6 +492,7 @@ impl ParsedBootDtInfo {
         let mut vtl0_alias_map = None;
         let mut memory_allocation_mode = MemoryAllocationMode::Host;
         let mut isolation = IsolationType::None;
+        let mut vtl2_reserved_range = MemoryRange::EMPTY;
 
         let parser = Parser::new(raw)
             .map_err(err_to_owned)
@@ -497,6 +521,7 @@ impl ParsedBootDtInfo {
                         vtl0_mmio: n_vtl0_mmio,
                         config_ranges: n_config_ranges,
                         partition_memory_map: n_partition_memory_map,
+                        vtl2_reserved_range: n_vtl2_reserved_range,
                         accepted_memory: n_accepted_memory,
                         vtl0_alias_map: n_vtl0_alias_map,
                         memory_allocation_mode: n_memory_allocation_mode,
@@ -509,6 +534,7 @@ impl ParsedBootDtInfo {
                     vtl0_alias_map = n_vtl0_alias_map;
                     memory_allocation_mode = n_memory_allocation_mode;
                     isolation = n_isolation;
+                    vtl2_reserved_range = n_vtl2_reserved_range;
                 }
 
                 _ if child.name.starts_with("memory@") => {
@@ -540,6 +566,7 @@ impl ParsedBootDtInfo {
             gic,
             memory_allocation_mode,
             isolation,
+            vtl2_reserved_range,
         })
     }
 }
@@ -854,6 +881,14 @@ mod tests {
                     vtl_usage: MemoryVtlType::VTL2_CONFIG,
                     igvm_type: MemoryMapEntryType::VTL2_PROTECTABLE,
                 }),
+                AddressRange::Memory(Memory {
+                    range: MemoryRangeWithNode {
+                        range: MemoryRange::new(0x40000..0x50000),
+                        vnode: 1,
+                    },
+                    vtl_usage: MemoryVtlType::VTL2_RESERVED,
+                    igvm_type: MemoryMapEntryType::VTL2_PROTECTABLE,
+                }),
                 AddressRange::Memory(Memory {
                     range: MemoryRangeWithNode {
                         range: MemoryRange::new(0x1000000..0x2000000),
@@ -890,6 +925,7 @@ mod tests {
                 mmio_size: Some(0x2000),
             },
             isolation: IsolationType::Vbs,
+            vtl2_reserved_range: MemoryRange::new(0x40000..0x50000),
         };
 
         let dt = build_dt(&orig_info).unwrap();

openhcl/openhcl_boot/src/dt.rs

@@ -509,6 +509,7 @@ pub fn write_dt(
                     ReservedMemoryType::Vtl2Config => MemoryVtlType::VTL2_CONFIG,
                     ReservedMemoryType::SidecarImage => MemoryVtlType::VTL2_SIDECAR_IMAGE,
                     ReservedMemoryType::SidecarNode => MemoryVtlType::VTL2_SIDECAR_NODE,
+                    ReservedMemoryType::Vtl2Reserved => MemoryVtlType::VTL2_RESERVED,
                 },
             )
         }),

openhcl/openhcl_boot/src/host_params/dt.rs

@@ -444,6 +444,7 @@ impl PartitionInfo {
             vtl2_ram: _,
             vtl2_full_config_region: vtl2_config_region,
             vtl2_config_region_reclaim: vtl2_config_region_reclaim_struct,
+            vtl2_reserved_region,
             partition_ram: _,
             isolation,
             bsp_reg,
@@ -466,6 +467,10 @@ impl PartitionInfo {
         );
         *vtl2_config_region_reclaim_struct = vtl2_config_region_reclaim;
         assert!(vtl2_config_region.contains(&vtl2_config_region_reclaim));
+        *vtl2_reserved_region = MemoryRange::new(
+            params.vtl2_reserved_region_start
+                ..(params.vtl2_reserved_region_start + params.vtl2_reserved_region_size),
+        );
         *bsp_reg = parsed.boot_cpuid_phys;
         cpus.extend(parsed.cpus.iter().copied());
         *com3_serial = parsed.com3_serial;

openhcl/openhcl_boot/src/host_params/mod.rs

@@ -53,7 +53,10 @@ pub struct PartitionInfo {
     /// Additional ram that can be reclaimed from the parameter region. Today,
     /// this is the whole device tree provided by the host.
     pub vtl2_config_region_reclaim: MemoryRange,
-    /// The full memory map provided by the host.
+    /// The vtl2 reserved region, that is reserved to both the kernel and
+    /// usermode.
+    pub vtl2_reserved_region: MemoryRange,
+    ///  The full memory map provided by the host.
     pub partition_ram: ArrayVec<MemoryEntry, MAX_PARTITION_RAM_RANGES>,
     /// The partiton's isolation type.
     pub isolation: IsolationType,
@@ -87,6 +90,7 @@ impl PartitionInfo {
             vtl2_ram: ArrayVec::new_const(),
             vtl2_full_config_region: MemoryRange::EMPTY,
             vtl2_config_region_reclaim: MemoryRange::EMPTY,
+            vtl2_reserved_region: MemoryRange::EMPTY,
             partition_ram: ArrayVec::new_const(),
             isolation: IsolationType::None,
             bsp_reg: 0,

openhcl/openhcl_boot/src/host_params/shim_params.rs

@@ -95,6 +95,10 @@ pub struct ShimParams {
     pub parameter_region_start: u64,
     /// The size of the parameter region.
     pub parameter_region_size: u64,
+    /// The base address of the VTL2 reserved region.
+    pub vtl2_reserved_region_start: u64,
+    /// The size of the VTL2 reserved region.
+    pub vtl2_reserved_region_size: u64,
     /// Isolation type supported by the boot shim.
     pub isolation_type: IsolationType,
     pub sidecar_entry_address: u64,
@@ -120,6 +124,8 @@ impl ShimParams {
             memory_size,
             parameter_region_offset,
             parameter_region_size,
+            vtl2_reserved_region_offset,
+            vtl2_reserved_region_size,
             sidecar_offset,
             sidecar_size,
             sidecar_entry_offset,
@@ -148,6 +154,9 @@ impl ShimParams {
             memory_size,
             parameter_region_start: shim_base_address.wrapping_add_signed(parameter_region_offset),
             parameter_region_size,
+            vtl2_reserved_region_start: shim_base_address
+                .wrapping_add_signed(vtl2_reserved_region_offset),
+            vtl2_reserved_region_size,
             isolation_type,
             sidecar_entry_address: shim_base_address.wrapping_add_signed(sidecar_entry_offset),
             sidecar_base: shim_base_address.wrapping_add_signed(sidecar_offset),
@@ -163,15 +172,17 @@ impl ShimParams {
     /// Get the base address of the secrets page.
     #[cfg(target_arch = "x86_64")]
     pub fn secrets_start(&self) -> u64 {
-        self.parameter_region_start
-            + loader_defs::paravisor::PARAVISOR_CONFIG_SECRETS_PAGE_INDEX * hvdef::HV_PAGE_SIZE
+        self.vtl2_reserved_region_start
+            + loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_SECRETS_PAGE_INDEX
+                * hvdef::HV_PAGE_SIZE
     }
 
     /// Get the size of the CPUID page.
     #[cfg(target_arch = "x86_64")]
     pub fn cpuid_start(&self) -> u64 {
-        self.parameter_region_start
-            + loader_defs::paravisor::PARAVISOR_CONFIG_CPUID_PAGE_INDEX * hvdef::HV_PAGE_SIZE
+        self.vtl2_reserved_region_start
+            + loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_CPUID_PAGE_INDEX
+                * hvdef::HV_PAGE_SIZE
     }
 
     /// Get the base address of the host provided device tree.

openhcl/openhcl_boot/src/main.rs

@@ -296,6 +296,7 @@ pub const MAX_RESERVED_MEM_RANGES: usize = 3 + sidecar_defs::MAX_NODES;
 #[derive(Clone, Copy, Debug, PartialEq, Eq)]
 enum ReservedMemoryType {
     Vtl2Config,
+    Vtl2Reserved,
     SidecarImage,
     SidecarNode,
 }
@@ -322,6 +323,15 @@ fn reserved_memory_regions(
             )
         }));
     }
+
+    // Add the VTL2 reserved region, if it exists.
+    if !partition_info.vtl2_reserved_region.is_empty() {
+        reserved.push((
+            partition_info.vtl2_reserved_region,
+            ReservedMemoryType::Vtl2Reserved,
+        ));
+    }
+
     reserved
         .as_mut()
         .sort_unstable_by_key(|(r, _typ)| r.start());
@@ -855,6 +865,7 @@ mod test {
             vtl2_ram: ArrayVec::new(),
             vtl2_full_config_region: MemoryRange::EMPTY,
             vtl2_config_region_reclaim: MemoryRange::EMPTY,
+            vtl2_reserved_region: MemoryRange::EMPTY,
             partition_ram: ArrayVec::new(),
             isolation: IsolationType::None,
             bsp_reg: cpus[0].reg as u32,

openhcl/underhill_core/src/loader/vtl2_config/mod.rs

@@ -14,13 +14,13 @@ use bootloader_fdt_parser::ParsedBootDtInfo;
 use hvdef::HV_PAGE_SIZE;
 use inspect::Inspect;
 use loader_defs::paravisor::ParavisorMeasuredVtl2Config;
-use loader_defs::paravisor::PARAVISOR_CONFIG_CPUID_PAGE_INDEX;
-use loader_defs::paravisor::PARAVISOR_CONFIG_CPUID_SIZE_PAGES;
 use loader_defs::paravisor::PARAVISOR_CONFIG_PPTT_PAGE_INDEX;
-use loader_defs::paravisor::PARAVISOR_CONFIG_SECRETS_PAGE_INDEX;
-use loader_defs::paravisor::PARAVISOR_CONFIG_SECRETS_SIZE_PAGES;
 use loader_defs::paravisor::PARAVISOR_CONFIG_SLIT_PAGE_INDEX;
 use loader_defs::paravisor::PARAVISOR_MEASURED_VTL2_CONFIG_PAGE_INDEX;
+use loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_CPUID_PAGE_INDEX;
+use loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_CPUID_SIZE_PAGES;
+use loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_SECRETS_PAGE_INDEX;
+use loader_defs::paravisor::PARAVISOR_RESERVED_VTL2_SNP_SECRETS_SIZE_PAGES;
 use memory_range::MemoryRange;
 use sparse_mmap::SparseMapping;
 use vm_topology::memory::MemoryRangeWithNode;
@@ -88,16 +88,17 @@ impl MeasuredVtl2Info {
 }
 
 #[derive(Debug)]
-/// Map of the portion of memory that contains the VTL2 parameters.
+/// Map of the portion of memory that contains the VTL2 parameters to read.
 ///
-/// On drop, this mapping zeroes out the specified config ranges.
+/// If configured, on drop this mapping zeroes out the specified config ranges.
 struct Vtl2ParamsMap<'a> {
     mapping: SparseMapping,
+    zero_on_drop: bool,
     ranges: &'a [MemoryRange],
 }
 
 impl<'a> Vtl2ParamsMap<'a> {
-    fn new(config_ranges: &'a [MemoryRange]) -> anyhow::Result<Self> {
+    fn new(config_ranges: &'a [MemoryRange], zero_on_drop: bool) -> anyhow::Result<Self> {
         // No overlaps.
         // TODO: Move this check to host_fdt_parser?
         if let Some((l, r)) = config_ranges
@@ -121,7 +122,7 @@ impl<'a> Vtl2ParamsMap<'a> {
 
         let dev_mem = fs_err::OpenOptions::new()
             .read(true)
-            .write(true)
+            .write(zero_on_drop)
             .open("/dev/mem")?;
         for range in config_ranges {
             mapping
@@ -130,14 +131,15 @@ impl<'a> Vtl2ParamsMap<'a> {
                     range.len() as usize,
                     dev_mem.file(),
                     range.start(),
-                    true,
+                    zero_on_drop,
                 )
                 .context("failed to memory map igvm parameters")?;
         }
 
         Ok(Self {
             mapping,
             ranges: config_ranges,
+            zero_on_drop,
         })
     }
 
@@ -152,25 +154,27 @@ impl<'a> Vtl2ParamsMap<'a> {
 
 impl Drop for Vtl2ParamsMap<'_> {
     fn drop(&mut self) {
-        let base = self
-            .ranges
-            .first()
-            .expect("already checked that there is at least one range")
-            .start();
-
-        for range in self.ranges {
-            self.mapping
-                .fill_at((range.start() - base) as usize, 0, range.len() as usize)
-                .unwrap();
+        if self.zero_on_drop {
+            let base = self
+                .ranges
+                .first()
+                .expect("already checked that there is at least one range")
+                .start();
+
+            for range in self.ranges {
+                self.mapping
+                    .fill_at((range.start() - base) as usize, 0, range.len() as usize)
+                    .unwrap();
+            }
         }
     }
 }
 
-/// Reads the VTL 2 parameters from the vtl-boot-data region.
+/// Reads the VTL 2 parameters from the config region and VTL2 reserved region.
 pub fn read_vtl2_params() -> anyhow::Result<(RuntimeParameters, MeasuredVtl2Info)> {
     let parsed_openhcl_boot = ParsedBootDtInfo::new().context("failed to parse openhcl_boot dt")?;
 
-    let mapping = Vtl2ParamsMap::new(&parsed_openhcl_boot.config_ranges)
+    let mapping = Vtl2ParamsMap::new(&parsed_openhcl_boot.config_ranges, true)
         .context("failed to map igvm parameters")?;
 
     // For the various ACPI tables, read the header to see how big the table
@@ -216,21 +220,26 @@ pub fn read_vtl2_params() -> anyhow::Result<(RuntimeParameters, MeasuredVtl2Info
         }
     };
 
+    // Read SNP specific information from the reserved region.
     let (cvm_cpuid_info, snp_secrets) = {
         if parsed_openhcl_boot.isolation == IsolationType::Snp {
+            let ranges = &[parsed_openhcl_boot.vtl2_reserved_range];
+            let reserved_mapping =
+                Vtl2ParamsMap::new(ranges, false).context("failed to map vtl2 reserved region")?;
+
             let mut cpuid_pages: Vec<u8> =
-                vec![0; (HV_PAGE_SIZE * PARAVISOR_CONFIG_CPUID_SIZE_PAGES) as usize];
-            mapping
+                vec![0; (PARAVISOR_RESERVED_VTL2_SNP_CPUID_SIZE_PAGES * HV_PAGE_SIZE) as usize];
+            reserved_mapping
                 .read_at(
-                    (PARAVISOR_CONFIG_CPUID_PAGE_INDEX * HV_PAGE_SIZE) as usize,
+                    (PARAVISOR_RESERVED_VTL2_SNP_CPUID_PAGE_INDEX * HV_PAGE_SIZE) as usize,
                     cpuid_pages.as_mut_slice(),
                 )
                 .context("failed to read cpuid pages")?;
             let mut secrets =
-                vec![0; (HV_PAGE_SIZE * PARAVISOR_CONFIG_SECRETS_SIZE_PAGES) as usize];
-            mapping
+                vec![0; (PARAVISOR_RESERVED_VTL2_SNP_SECRETS_SIZE_PAGES * HV_PAGE_SIZE) as usize];
+            reserved_mapping
                 .read_at(
-                    (HV_PAGE_SIZE * PARAVISOR_CONFIG_SECRETS_PAGE_INDEX) as usize,
+                    (PARAVISOR_RESERVED_VTL2_SNP_SECRETS_PAGE_INDEX * HV_PAGE_SIZE) as usize,
                     secrets.as_mut_slice(),
                 )
                 .context("failed to read secrets page")?;